The periodic jobs are currently getting registered per each worker
which means that in cases with large number of workers, the APIs
for services such as Heat and Keystone will be hit very hard.
This patch resolves this issue by registering the jobs only to the
main process, ensuring that they run once per instance (or group
of workers).
Closes-Bug: #1702349
Change-Id: If9e13effc14fd35e646d02bb4f568e79786aa958