Added gerritbot to openstack-ansible channel

This change adds the gerrit irc bot to the openstack-ansible channel.
The bot has been setup to watch the branches **stable/icehouse**,
**stable/juno**, and **proposed/juno**.

Change-Id: I00a373744faeef9a8243c9df5edd8c83775f3cd8
Merge "Added gerritbot to openstack-ansible channel"