restore the lost (in mysql-5.6) bugfix for

Bug#13510739 63775: SERVER CRASH ON HANDLER READ NEXT AFTER DELETE RECORD.

storage/innobase/row/row0sel.cc

@@ -4686,7 +4686,8 @@ row_search_for_mysql(
 		applicable to unique secondary indexes. Current behaviour is
 		to widen the scope of a lock on an already delete marked record
 		if the same record is deleted twice by the same transaction */
-		if (index == clust_index && unique_search) {
+		if (index == clust_index && unique_search
+		    && !prebuilt->used_in_HANDLER) {                  
 			err = DB_RECORD_NOT_FOUND;
 
 			goto normal_return;