Prevent puppet certname with mixed-case hostnames

Puppet requires that certname be all lower case. Sometimes systems will
have mixed case in their FQDN, but the lower case should be equivalent
for most if not all cases.

Note that this is discussed upstream in puppet's bug trackers here:

http://projects.puppetlabs.com/issues/1168

and here:

https://tickets.puppetlabs.com/browse/PUP-2551

Change-Id: I91aae733bf6c82abc632cac0726b129de88d9b34

modules/openstack_project/templates/puppet.conf.erb

@@ -4,7 +4,7 @@ vardir=/var/lib/puppet
 ssldir=/var/lib/puppet/ssl
 rundir=/var/run/puppet
 server=<%= @puppetmaster_server %>
-certname=<%= @certname %>
+certname=<%= @certname.downcase %>
 pluginsync=true