Fix OFTC/Freenode channels
Fix OFTC/Freenode channels

The previous change updated all links to go to OFTC, including some from
third parties. Revert those back as they still seem to be on Freenode.

Change-Id: Iceaa2af8a16f4b94c32745d45726f181bfec32e6

openstack/api-site,openstack/api-site,openstack/api-site,openstack/api-site