MDEV-11422 rpl.rpl_parallel_optimistic_nobinlog failed in buildbot with "InnoDB: Killing connection failed Deadlock"
MDEV-11422 rpl.rpl_parallel_optimistic_nobinlog failed in buildbot with "InnoDB: Killing connection failed Deadlock"

innobase_kill_query(): Remove the bogus warning message
(for the valid outcome err==DB_DEADLOCK) that was added in

commit fec844aca88e1c6b9c36bb0b811e92d9d023ffb9
Author: Jan Lindström <jan.lindstrom@mariadb.com>
Date:   Tue Sep 6 09:43:16 2016 +0300

    Merge InnoDB 5.7 from mysql-5.7.14.

Also, remove some redundant variables and add a debug assertion for
enforcing the proper outcome of lock_trx_handle_wait().

natsys/mariadb_10.2,natsys/mariadb_10.2,natsys/mariadb_10.2,natsys/mariadb_10.2,natsys/mariadb_10.2,natsys/mariadb_10.2,natsys/mariadb_10.2,natsys/mariadb_10.2,natsys/mariadb_10.2,natsys/mariadb_10.2,natsys/mariadb_10.2