Fix for the nailgun syncdb call
Fix for the nailgun syncdb call

Fixed the logic which previously caused deadlocks in the nailgun's
db during a migration process, since it has been running having
nailgun's process on-line. Now it stops the processes before migrating
the database and starts them after.

Closes-Bug: #1644619

aepifanov/mos_mu,aepifanov/mos_mu