Currently InternalError is being handled for detecting MariaDB/Galera
deadlocks but recently we have seen a variant that raises
OperationalError instead. Because it's not being detected, usage of the
@retry_on_deadlock decorator is not performing retries in those cases.
This adds handling of OperationalError for detecting this deadlock.
Closes-Bug: #2057987
Change-Id: I6ff3667b35ea38a2d3c258f810a55eda9abe465e