Enable ceilometer services using new plugin model

[venkatamahesh]

http://docs.openstack.org/developer/magnum/dev/dev-manual-devstack.html

In the above link, instead of enabling each ceilometer service, we can enable ceilometer using plugin so that all ceilometer services
are enabled

Reference : https://github.com/openstack/ceilometer/blob/master/devstack/plugin.sh#L7

[venkatamahesh (venkatamaheshkotha)]

I had submitted a patch :
https://review.openstack.org/#/c/224800/

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/224800
Committed: https://git.openstack.org/cgit/openstack/magnum/commit/?id=bab9694fd2a039639106e10981ce9a260e3aeaa0
Submitter: Jenkins
Branch: master

commit bab9694fd2a039639106e10981ce9a260e3aeaa0
Author: venkatamahesh <email address hidden>
Date: Thu Sep 17 21:20:39 2015 +0530

    Enabled ceilometer services using new model

    By using new plugin model by default all ceilometer
    services are enabled. So there is no need to enable all
    services individually

    Closes-Bug: #1497706
    Change-Id: Id96f7fe13872ba42484d97266ac4d68ae7ca1e73

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/231034
Committed: https://git.openstack.org/cgit/openstack/magnum/commit/?id=a8ed34ac7d3280b1c91936d5a5d1da4ad1fbbc79
Submitter: Jenkins
Branch: master

commit a8ed34ac7d3280b1c91936d5a5d1da4ad1fbbc79
Author: Hongbin Lu <email address hidden>
Date: Mon Oct 5 10:57:18 2015 -0400

    Enabled ceilometer using plugin model

    Devstack plugin, such as ceilometer, should not be enabled in
    settings, since the path of the plugin is not available at that time.
    Therefore, users have to manually enable it in local.conf, if they
    run devstack locally.

    Closes-Bug: #1497706
    Change-Id: Idca09449ab5a3a5276282ffbcbb0aa73f35c34ae