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 #284 from dirkmueller/release/roxy/master

Fix localisation of KSM
Drop unused template
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