Revert 4ce6c3f3. Fixes drag and drop on my...

Revert 4ce6c3f3. Fixes drag and drop on my system. Adding quotes to a filename in C/C++ isn't going to change anything (it would on a command line given the way getopt works). Tested with a file named "/home/dionoea/media/test test/redefined :ni=ntendo.mpg".

modules/gui/qt4/main_interface.cpp

@@ -1095,7 +1095,7 @@ void MainInterface::dropEvent(QDropEvent *event)
      bool first = true;
      foreach( QUrl url, mimeData->urls() )
      {
-        QString s = "\"" + url.toString() + "\"";
+        QString s = url.toString();
         if( s.length() > 0 ) {
             playlist_Add( THEPL, qtu(s), NULL,
                           PLAYLIST_APPEND | (first ? PLAYLIST_GO:0),