MDEV-7458: Deadlock in parallel replication can allow following transaction to start replicating too early
MDEV-7458: Deadlock in parallel replication can allow following transaction to start replicating too early

In parallel replication, don't rollback inside ha_commit_trans() in case of
error.

The rollback will be done later, but the parallel replication code needs to
run unmark_start_commit() before the rollback to properly control the
sequencing of transactions.

I did not manage to come up with a reliable automatic test case for this, but
I tested it manually.

ollie314/server,davidl-zend/zenddbi,davidl-zend/zenddbi,flynn1973/mariadb-aix,ollie314/server,natsys/mariadb_10.2,davidl-zend/zenddbi,flynn1973/mariadb-aix,ollie314/server,natsys/mariadb_10.2,natsys/mariadb_10.2,ollie314/server,natsys/mariadb_10.2,flynn1973/mariadb-aix,natsys/mariadb_10.2,natsys/mariadb_10.2,davidl-zend/zenddbi,flynn1973/mariadb-aix,ollie314/server,ollie314/server,davidl-zend/zenddbi,davidl-zend/zenddbi,natsys/mariadb_10.2,flynn1973/mariadb-aix,flynn1973/mariadb-aix,natsys/mariadb_10.2,flynn1973/mariadb-aix,ollie314/server,natsys/mariadb_10.2,natsys/mariadb_10.2,davidl-zend/zenddbi,davidl-zend/zenddbi,natsys/mariadb_10.2,ollie314/server,ollie314/server,flynn1973/mariadb-aix,davidl-zend/zenddbi,ollie314/server,flynn1973/mariadb-aix,flynn1973/mariadb-aix,flynn1973/mariadb-aix,davidl-zend/zenddbi,davidl-zend/zenddbi,ollie314/server