Fix RBD with external Ceph without Cephx use case

When a rbd_user is set in the cinder.conf, Nova will re-use
that username in order to look up a libvirt secret, which fails,
even though none is stored and none is needed.

Make it more explicit that the user name needs to be emptied
and removed from the cinder config (set to default "None")
Code style fix
Merge pull request #142 from dirkmueller/release/roxy/master

Fix RBD with external Ceph without Cephx use case
Moved role constraints into model and removed edit deployment

(cherry picked from commit 6af9728f3ea5cba675f3c29de4f3bb59a132ac94)
Merge pull request #154 from vuntz/release/roxy/master

Moved role constraints into model and removed edit deployment
Removed the single assignment block from constraints
Merge pull request #155 from tboerger/feature/roxy/fix-constraints

Removed the single assignment block from constraints
Fix to work when keystone is behind haproxy
Use new helpers to get hostnames for endpoints
HAProxy support for cinder-api
Fix case of OpenStack in barclamp description
Use correct glance host when glance is behind haproxy
Merge pull request #151 from vuntz/haproxy

Work with keystone behind haproxy + haproxy for cinder-api
Merge branch 'release/roxy/master' into roxy-sync

Conflicts:
	chef/cookbooks/cinder/recipes/api.rb
	chef/cookbooks/cinder/templates/default/api-paste.ini.erb
	crowbar_framework/app/models/cinder_service.rb
Merge pull request #158 from vuntz/roxy-sync

Merge roxy branch into stoney