Do not pull ceph.conf for roles unrelated to Ceph

If ceph::conf invokes 'ceph-deploy config pull' before primary
controller is done (e.g. as part of mongodb role), it will fail and
disrupt deployment.

This commit also partially cleans up the mess introduced in
f50248cea09b320d276cf72321ed29b411fd4b55: only ceph package has a
service that can be restarted, setting up notifications for anything
else is meaningless.

Change-Id: I887bd38209752e634c11d45e4d69e0d24972d5f6
Closes-bug: #1316524
Merge "Do not pull ceph.conf for roles unrelated to Ceph"