Fix problem with nova --version

Update to latest openstack.common.version.py and fix __init__.py
to get "nova --version" to work properly again

Fixes LP# 1165325

Change-Id: I29e54cd4cf79759407f3967518e9be575abd994a
Fixing shell command 'service-disable' description

Fixes: bug #1166217
Change-Id: I0ba609750551540f9cd91492191b222961e99fb1
Merge "Fix problem with nova --version"