Adding #openstack-containers IRC bot

This is a dedicated IRC channel for discussion
about Operating System container support in
OpenStack. The members of the OpenStack
Containers Team will idle in this channel:

https://wiki.openstack.org/wiki/Teams/Containers

Change-Id: I9ec77969f926e8ced912ce194f7d6fae6a0e2e4d
Merge "Adding #openstack-containers IRC bot"