Add branch creation acl for nova-lxd project.
Add branch creation acl for nova-lxd project.

nova-lxd didn't have branch creation permissions granted to anyone.
This is a problem when it comes time to release. This patch adds
the acl so that nova-lxd-core can create branches.

Change-Id: I66fc66ba0eae269390f40a9fd679d73c3fc0ccc6

Tesora/tesora-project-config,openstack-infra/project-config,Tesora/tesora-project-config,openstack-infra/project-config