* perform all keystone-manage commands only as keystone user
* as it possible to override keystone user in init class
we should also have an ability to override it in db::sync class
* ensure that fernet key directory is created before fernet
setup command and it's owned by keystone user
Closes-bug: #1604884
Change-Id: Ib90d8e2259b9a650a2edb5f0baf0e68451b9abf6
c0fcdb5a0e