
Syncs openstack.common.periodic_task to commit 0848516902444ca83dd4998655cae3901d038d (https://review.openstack.org/#/c/148854/). This patch also makes service start running periodic tasks after init_host() is called. Change-Id: I63ee4ce30b3684e53158fe5f985efd04e4e88fef Implements: blueprint driver-periodic-tasks