Preinstall lsb_release on RHEL.

Updates the puppet install scripts so that we pre-install
lsb_release on RHEL distros. We *think* this fixes an
issue where lsbdistcodename wasn't getting set correctly
and was causing subsequent puppet failures like this:

lsbdistcodename fact not available: release parameter required at
/etc/puppet/modules/apt/manifests/ppa.pp

Change-Id: I1758ee8be9a599e17f1ccb98fc95b2b4f29916f7
Reviewed-on: https://review.openstack.org/23111
Reviewed-by: Jeremy Stanley <fungi@yuggoth.org>
Approved: Clark Boylan <clark.boylan@gmail.com>
Reviewed-by: Clark Boylan <clark.boylan@gmail.com>
Tested-by: Jenkins