x11-wm/qtfm Fix build with Clang6

mymodel.cpp:166:12: error: no viable conversion from returned
	value of type 'bool' to function return type 'QString'

Presumably, false -> 0 -> NULL -> QString(char *) was at some point a
viable conversion. Return an empty QString explicitly.

Reported by:	linimon

x11-fm/qtfm/files/patch-src_mymodel.cpp

@@ -1,159 +1,11 @@
---- src/mymodel.cpp.orig	2012-07-11 18:21:24.302333223 -0500
-+++ src/mymodel.cpp	2012-07-11 18:59:06.428956406 -0500
-@@ -21,7 +21,6 @@
+--- src/mymodel.cpp.orig	2018-07-04 09:21:07 UTC
++++ src/mymodel.cpp
+@@ -166,7 +166,7 @@ QString myModel::filePath(const QModelIn
  
- #include <mainwindow.h>
- #include "mymodel.h"
--#include <sys/inotify.h>
- #include <unistd.h>
- #include <sys/ioctl.h>
+     if(item) return item->absoluteFilePath();
  
-@@ -63,10 +62,8 @@ myModel::myModel(bool realMime)
- 
-     iconFactory = new QFileIconProvider();
- 
--    inotifyFD = inotify_init();
--    notifier = new QSocketNotifier(inotifyFD, QSocketNotifier::Read, this);
--    connect(notifier, SIGNAL(activated(int)), this, SLOT(notifyChange()));
--    connect(&eventTimer,SIGNAL(timeout()),this,SLOT(eventTimeout()));
-+    watcher = new QFileSystemWatcher(this);
-+    connect(watcher, SIGNAL(directoryChanged(QString)), this, SLOT(notifyChange(QString)));
- 
-     realMimeTypes = realMime;
- }
-@@ -189,62 +186,9 @@ QString myModel::getMimeType(const QMode
+-    return false;
++    return QString();
  }
  
  //---------------------------------------------------------------------------------------
--void myModel::notifyChange()
-+void myModel::notifyChange(QString const& path)
- {
--    notifier->setEnabled(0);
--
--    int buffSize = 0;
--    ioctl(inotifyFD, FIONREAD, (char *) &buffSize);
--
--    QByteArray buffer;
--    buffer.resize(buffSize);
--    read(inotifyFD,buffer.data(),buffSize);
--    const char *at = buffer.data();
--    const char * const end = at + buffSize;
--
--    while (at < end)
--    {
--        const inotify_event *event = reinterpret_cast<const inotify_event *>(at);
--
--        int w = event->wd;
--
--        if(eventTimer.isActive())
--        {
--            if(w == lastEventID)
--                eventTimer.start(40);
--            else
--            {
--                eventTimer.stop();
--                notifyProcess(lastEventID);
--                lastEventID = w;
--                eventTimer.start(40);
--            }
--        }
--        else
--        {
--            lastEventID = w;
--            eventTimer.start(40);
--        }
--
--        at += sizeof(inotify_event) + event->len;
--    }
--
--    notifier->setEnabled(1);
--}
--
--//---------------------------------------------------------------------------------------
--void myModel::eventTimeout()
--{
--    notifyProcess(lastEventID);
--    eventTimer.stop();
--}
--
--//---------------------------------------------------------------------------------------
--void myModel::notifyProcess(int eventID)
--{
--    if(watchers.contains(eventID))
--    {
--        myModelItem *parent = rootItem->matchPath(watchers.value(eventID).split(SEPARATOR));
-+        myModelItem *parent = rootItem->matchPath(path.split(SEPARATOR));
- 
-         if(parent)
-         {
-@@ -265,9 +209,7 @@ void myModel::notifyProcess(int eventID)
-                     //must of been deleted, remove from model
-                     if(child->fileInfo().isDir())
-                     {
--                        int wd = watchers.key(child->absoluteFilePath());
--                        inotify_rm_watch(inotifyFD,wd);
--                        watchers.remove(wd);
-+                        watcher->removePath(child->absoluteFilePath());
-                     }
-                     beginRemoveRows(index(parent->absoluteFilePath()),child->childNumber(),child->childNumber());
-                     parent->removeChild(child);
-@@ -282,20 +224,19 @@ void myModel::notifyProcess(int eventID)
-                 endInsertRows();
-             }
-         }
--    }
--    else
--    {
--        inotify_rm_watch(inotifyFD,eventID);
--        watchers.remove(eventID);
--    }
-+        else
-+        {
-+                watcher->removePath(path);
-+        }
- }
- 
- //---------------------------------------------------------------------------------
--void myModel::addWatcher(myModelItem *item)
-+void myModel::addToWatcher(myModelItem *item)
- {
-     while(item != rootItem)
-     {
--        watchers.insert(inotify_add_watch(inotifyFD, item->absoluteFilePath().toLocal8Bit(), IN_MOVE | IN_CREATE | IN_DELETE),item->absoluteFilePath()); //IN_ONESHOT | IN_ALL_EVENTS)
-+        if (!watcher->directories().contains(item->absoluteFilePath()))
-+            watcher->addPath(item->absoluteFilePath());
-         item->watched = 1;
-         item = item->parent();
-     }
-@@ -308,7 +249,7 @@ bool myModel::setRootPath(const QString&
- 
-     myModelItem *item = rootItem->matchPath(path.split(SEPARATOR));
- 
--    if(item->watched == 0) addWatcher(item);
-+    if(item->watched == 0) addToWatcher(item);
- 
-     if(item->walked == 0)
-     {
-@@ -382,10 +323,7 @@ void myModel::refresh()
- {
-     myModelItem *item = rootItem->matchPath(QStringList("/"));
- 
--    //free all inotify watches
--    foreach(int w, watchers.keys())
--        inotify_rm_watch(inotifyFD,w);
--    watchers.clear();
-+    watcher->removePaths(watcher->directories());
- 
-     beginResetModel();
-     item->clearAll();
-@@ -840,9 +778,7 @@ bool myModel::remove(const QModelIndex &
-         QFileInfo info(children.at(i));
-         if(info.isDir())
-         {
--            int wd = watchers.key(info.filePath());
--            inotify_rm_watch(inotifyFD,wd);
--            watchers.remove(wd);
-+            watcher->removePath(info.filePath());
-             error |= QDir().rmdir(info.filePath());
-         }
-         else error |= QFile::remove(info.filePath());