Allow users to configure the CM pipeline interval

The patch allows users to configure the ceilometer pipeline interval.
In localrc, we can add CEILOMETER_PIPELINE_INTERVAL=10 to handle the
pipeline each 10 seconds instead of the default 10 minutes.

Change-Id: Ic5216adbdfd70ade38912871ac6df3be732bf780
Enable/disable ironic in tempest config

In order to run tempest tests for Ironic in devstack
the availability of the Ironic service must be set in
the tempest config.

This patch adds a shortcut for Ironic services and sets
availability of Ironic in tempest config.

Change-Id: I206fc2ea13412ceb128f8bfe90c153348d6f2f3e
Merge "Enable/disable ironic in tempest config"
Merge "Allow users to configure the CM pipeline interval"
Merge branch 'master' of github.com:openstack-dev/devstack