Qt4: simplify and improve playlist item folder exploration

Unfortunately, there is currently no way to determine whether the
MRL scheme uses file paths (e.g. file, dir, vdr, zip...) or not, so
we always try.

Anyway, the folder browsing menu item should not be visible at all when
the item is not a local file. So there is no need to deal with that
failure care here.

modules/gui/qt4/components/playlist/playlist_model.cpp

@@ -1045,39 +1045,29 @@ void PLModel::popupSave()
 
 void PLModel::popupExplore()
 {
+    char *uri = NULL, *path = NULL;
+
     PL_LOCK;
     playlist_item_t *p_item = playlist_ItemGetById( p_playlist, i_popup_item );
     if( p_item )
     {
         input_item_t *p_input = p_item->p_input;
-        char *psz_meta = input_item_GetURI( p_input );
-        PL_UNLOCK;
-        if( psz_meta )
-        {
-            const char *psz_access;
-            const char *psz_demux;
-            char  *psz_path;
-            input_SplitMRL( &psz_access, &psz_demux, &psz_path, psz_meta );
-
-            if( !EMPTY_STR( psz_access ) && (
-                   !strncasecmp( psz_access, "file", 4 ) ||
-                   !strncasecmp( psz_access, "dire", 4 ) ))
-            {
-#if defined( WIN32 ) || defined( __OS2__ )
-                /* Qt openURL doesn't know to open files that starts with a / or \ */
-                if( psz_path[0] == '/' || psz_path[0] == '\\'  )
-                    psz_path++;
-#endif
+        uri = input_item_GetURI( p_input );
+    }
+    PL_UNLOCK;
 
-                QFileInfo info( qfu( decode_URI( psz_path ) ) );
-                QDesktopServices::openUrl(
-                        QUrl::fromLocalFile( info.absolutePath() ) );
-            }
-            free( psz_meta );
-        }
+    if( uri != NULL )
+    {
+        path = make_path( uri );
+        free( uri );
     }
-    else
-        PL_UNLOCK;
+    if( path == NULL )
+        return;
+
+    QFileInfo info( qfu( path ) );
+    free( path );
+
+    QDesktopServices::openUrl( QUrl::fromLocalFile( info.absolutePath() ) );
 }
 
 void PLModel::popupAddNode()