qt4: remove b_is_node and use childCount() > 0 instead in playlist_model

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

@@ -54,7 +54,6 @@ void PLItem::init( playlist_item_t *_playlist_item, PLItem *parent, PLModel *m,
     i_id       = _playlist_item->i_id;           /* Playlist item specific id */
     model      = m;               /* PLModel (QAbsmodel) */
     i_type     = -1;              /* Item type - Avoid segfault */
-    b_is_node  = _playlist_item->i_children > -1;
     p_input    = _playlist_item->p_input;
     vlc_gc_incref( p_input );
 
@@ -144,7 +143,6 @@ void PLItem::update( playlist_item_t *p_item )
 
     /* Useful for the model */
     i_type = p_item->p_input->i_type;
-    b_is_node = p_item->i_children > -1;
 
     i_showflags = parentItem ? parentItem->i_showflags : i_showflags;
 }

modules/gui/qt4/components/playlist/playlist_item.hpp

@@ -66,7 +66,6 @@ protected:
     int i_type;
     int i_id;
     int i_showflags;
-    bool b_is_node;
     input_item_t *p_input;
 
 private:

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

@@ -146,7 +146,7 @@ Qt::ItemFlags PLModel::flags( const QModelIndex &index ) const
     }
     else
     {
-        if ( item->b_is_node &&
+        if ( (item->childCount() > 0) &&
             ( rootItem->p_input == pl_input ||
             rootItem->p_input == ml_input ) )
                 flags |= Qt::ItemIsDropEnabled;