merge from 5.1

storage/innobase/row/row0vers.c

@@ -209,17 +209,6 @@ row_vers_impl_x_locked_off_kernel(
 		prev_trx_id = row_get_rec_trx_id(prev_version, clust_index,
 						 clust_offsets);
 
-		/* If the trx_id and prev_trx_id are different and if
-		the prev_version is marked deleted then the
-		prev_trx_id must have already committed for the trx_id
-		to be able to modify the row. Therefore, prev_trx_id
-		cannot hold any implicit lock. */
-		if (vers_del && trx_id != prev_trx_id) {
-
-			mutex_enter(&kernel_mutex);
-			break;
-		}
-
 		/* The stack of versions is locked by mtr.  Thus, it
 		is safe to fetch the prefixes for externally stored
 		columns. */