Completely remove etc/savanna dir

Since https://review.openstack.org/#/c/80043/ is about to be merged
it's time to remove etc/savanna dir

Change-Id: I9f5f4e62cf0c8cce3e694e539939223bf65959bb
Partial-Implements: blueprint savanna-renaming-service
Merge "Completely remove etc/savanna dir"