Update default_mods.pp

This should cover the case that on a Amazon AWS Image that is based on RHEL6/CentOS6 but the Apache in version 2.4 should be used, to avoid to load the non existing systemd Apache module.
Update to include auth_required for versions other than 2.4 but keeping at the top of the section
Add support to set SSLCARevocationCheck on Apache 2.4

Apache 2.4 needs an additional SSLCARevocationCheck directive to enable
checking of a CRL, e.g. for a Puppet master vhost.

See https://github.com/puppetlabs/puppet/commit/b02af7e05d9b9a3bc23474933d8d7f6cd6191158
for more background
Merge pull request #870 from cyberious/DirectoriesAuthRequire

Update to include auth_required for versions other than 2.4 but keeping at the top of the section
Merge pull request #866 from domcleal/ssl-crl-check

Add support to set SSLCARevocationCheck on Apache 2.4
Merge pull request #865 from p7s1-wschreiner/patch-1

Update default_mods.pp