Add XAPI config to quantum rootwrap for XS/XCP.

 * Supports blueprint xenapi-ovs

Change-Id: I902458ec26cd07e94fe50bb3648efa75658ccba3
fix ceilometer ENABLE_SERVICES comment

- keep it aligned with the Ceilometer doc

Change-Id: Ib1ca0cfbeafc61723e5d4fe79da6355db7d76f0c
Fixes: bug #1179590
Merge "fix ceilometer ENABLE_SERVICES comment"
Merge "Add XAPI config to quantum rootwrap for XS/XCP."
Merge branch 'master' of github.com:openstack-dev/devstack