According to https://review.openstack.org/#/c/419031/ the only
command to be executed to populate watcher DB is:
watcher-db-manage --config-file /etc/watcher/watcher.conf upgrade head
create_schema command is not longer needed, and in fact is not
creating table apscheduler_jobs properly.
Note that p-o-i jobs keep working because the version of APScheduler
currently in RDO creates table apscheduler_jobs automatically
in SQLAlchemyJobStore initialization. This is not longer true
in recent versions, so it will break as soon as APScheduler is
updated, so let's fix it.
[1] bf99bff8ea (diff-c47a8d544459e39b2dc3dfeb50a4ec6bR55)
Change-Id: If0338362f9b7b9c90390a836a40b0036adc958a3
85d0a023a4