Add logging to #openstack-relmgr-office

People have been asking that 1-to-1 meetings between release managers
and PTLs be logged and easily filtered, so a specific channel was set
up to that effect (#openstack-relmgr-office). This change requests
that it is permanently logged using eavesdrop.

openstackinfra was added to that channel with founder rights.

Change-Id: Ie7d37b5a296c6ac691a4135f484c6f6b9e40e3c9
Merge "Add logging to #openstack-relmgr-office"