Add periodic jobs for stable/grizzly

This commit adds 3 periodic runs for the grizzly stable branch. A
full tempest run with mysql and postgres, and also a smoke run with
quantum.

Change-Id: Id61ab6a423146947c55812feb8fbf00711ee8f84
Reviewed-on: https://review.openstack.org/26100
Reviewed-by: James E. Blair <corvus@inaugust.com>
Approved: Jeremy Stanley <fungi@yuggoth.org>
Reviewed-by: Jeremy Stanley <fungi@yuggoth.org>
Tested-by: Jenkins