Update references with new Mailing List location

Yesterday, openstack@lists.launchpad.org was migrated with
all users to openstack@list.openstack.org.

This patch updates references to the old mailing list with the
new, to ensure that people encountering them don't accidentally
try and join the old list!

Change-Id: I59c6268637dea8ca06cdb8bf28808d1b59562ff7
Fix redirect problem for new user guide

Change-Id: If969b54dadf91d235b3ab2bf20aebd81620b2fc8
author: diane fleming
Merge "Fix redirect problem for new user guide"
Merge "Update references with new Mailing List location"