For mysql with syslog, make local logs copy and provide rotation

For syslog mode, save a local copy of *all* mysql logs to /var/log/mysqld.log
and add it ro retation plans as well.
(Does not change remote logging headers)

Closes bug: #1275124

Change-Id: I322594fdf47329e914526168eda42f9dd16a3201
Signed-off-by: Bogdan Dobrelya <bdobrelia@mirantis.com>
Merge "For mysql with syslog, make local logs copy and provide rotation"