Avoid re-creating Nova home directory when not in usegitrepo mode

This is always bound to conflict with the packages, and we're
fine with having any home directory being created. The one
configured by the packages should be the correct one.

This also simplifies the code a little.
Update template of nova.conf to Havana
Merge pull request #286 from vuntz/cleanup-templates

Drop unused template
Merge pull request #283 from dirkmueller/nova_conf_update

Update template of nova.conf to Havana
Merge pull request #282 from dirkmueller/ssh_cleanup

Avoid re-creating Nova home directory when not in usegitrepo mode
Update api-paste.ini

Enable V3 API Route
Fix keystone signing dir
Fix a few oversights in nova.conf.erb merging
Merge pull request #287 from dirkmueller/nova_conf_update

Nova conf update
Remove support for nova-network
Remove unused variable
Add migration script for nova-network removal