The puppetlabs-rabbitmq module introduce a new feature related to the
erlang_cookie parameter change (the database must be wiped if the cookie is
changed), the parameter wipe_db_on_cookie_change is configured to false by
default.
But we're not setting up a rabbitmq cluster and we're not using pacemaker in
beaker CI tests, so we just remove the erlang cookie parameter change.
Change-Id: I3381092f5503f4a50ab1636cef829145ef22d230
Closes-Bug: #1468444