Fix senlin workers and events
Fix senlin workers and events

Remove deprecation warning about service_token_roles_required
Set number of engine workers to avoid too many resources consuming.
Senlin can poll events from ceilometer when is enabled.

Closes-Bug: #1679697
Change-Id: I8b13d1f492344ca0b65020eb56f0e016c6bb6369

dardelean/kolla-ansible,dardelean/kolla-ansible,dardelean/kolla-ansible