bug 153, 1066: Fix search in bookmark manager.

test_search() was supposed to compare bookmark titles with
strcasestr(), but in commit 311d95358d
"bug 153, 1066: Convert bookmarks to/from UTF-8 when searching."
on 2009-02-08, I inadvertently changed that to strcasecmp(), even
while adding a comment about why strcasestr() is needed.  strcasestr()
returns non-NULL if the strings match, and strcasecmp() returns
nonzero if they differ, so the search didn't work at all.

src/bookmarks/dialogs.c

@@ -687,8 +687,8 @@ test_search(struct listbox_item *item, void *data_, int *offset)
 			}
 
 			if (title) {
-				ctx->found = strcasecmp(title,
-							ctx->title);
+				ctx->found = (strcasestr(title, ctx->title)
+					      != NULL);
 				mem_free(title);
 			}
 			/** @todo Tell the user that the string could