Fixed #272: the list of tracks was not cleared before reloading

all track files, resulting in more and more tracks accumulating
in the track list each time a track is (un)installed.
In case of uninstalling a track, the track would remain in the
list, and if this track is selected, STK crashed.


git-svn-id: svn+ssh://svn.code.sf.net/p/supertuxkart/code/main/trunk@8908 178a84e3-b1eb-0310-8ba1-8eac791a3b58

src/tracks/track_manager.cpp

@@ -122,6 +122,7 @@ void TrackManager::loadTrackList()
     m_arena_group_names.clear();
     m_arena_groups.clear();
     m_track_avail.clear();
+    m_tracks.clear();
     
     for(unsigned int i=0; i<m_track_search_path.size(); i++)
     {