Revert "Partially work around a picture link in libmpeg2."

This reverts commit f18192c6.
It fixed a few streams while breaking a few others one.

modules/codec/libmpeg2.c

@@ -466,13 +466,8 @@ static picture_t *DecodeBlock( decoder_t *p_dec, block_t **pp_block )
             if( p_sys->p_info->discard_fbuf &&
                 p_sys->p_info->discard_fbuf->id )
             {
-
-                picture_t *p_old = p_sys->p_info->discard_fbuf->id;
-
-                if( p_old->i_status == RESERVED_PICTURE && p_old->date == 0 )
-                    p_dec->pf_vout_buffer_del( p_dec, p_old );
-                else
-                    p_dec->pf_picture_unlink( p_dec, p_old );
+                p_dec->pf_picture_unlink( p_dec,
+                                          p_sys->p_info->discard_fbuf->id );
             }
 
             /* For still frames */