macosx: select the right playlist item when a new file in playlist begins to play

should fix #4812 for vlc 2
Signed-off-by: Felix Paul Kühne <fkuehne@videolan.org>
(cherry picked from commit 9ae001675da6a878b4bdbe3fc4c693bd9a802013)
Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>

modules/gui/macosx/playlist.m

@@ -597,6 +597,10 @@
             [o_outline_view expandItem: o_item];
         }
     }
+
+    id o_item = [o_outline_dict objectForKey:[NSString stringWithFormat: @"%p", p_item]];
+    NSInteger i_index = [o_outline_view rowForItem:o_item];
+    [o_outline_view selectRowIndexes:[NSIndexSet indexSetWithIndex:i_index] byExtendingSelection:NO];
 }
 
 /* Check if p_item is a child of p_node recursively. We need to check the item