Fix #2720 for master also. Finally that's not an hack as the code is build to

stop the playlist just after removing the playing item (so that's ok to stop
the PL even when it's empty).

(cherry picked from commit be1f4305f1203ccf5acc402fd2cc80dde3f5b1cd)
Signed-off-by: Rémi Duraffort <ivoire@videolan.org>

src/playlist/control.c

@@ -104,7 +104,7 @@ static int PlaylistVAControl( playlist_t * p_playlist, int i_query, va_list args
     if( !vlc_object_alive( p_playlist ) )
         return VLC_EGENERIC;
 
-    if( playlist_IsEmpty( p_playlist ) )
+    if( playlist_IsEmpty( p_playlist ) && i_query != PLAYLIST_STOP )
         return VLC_EGENERIC;
 
     switch( i_query )