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
changed from depreciated apache::dev to apache::mod::dev
Created the apache::mod::shib class to install the mod_shib Shibboleth module for Apache2

http://shibboleth.net/
define a shibboleth sso resource
Stubbing out metadata for shib
Download metadata and metadata certificate from provider.
Create a resource for downloading attribute map files
Define the back end certifiate as a resource because there will only be one.
Documentation (and a few tweaks to make code match docs)
 Update and expand spec tests, including code fixes to match expected behaviour.
Stripping out the shibboleth daemon config out into a separate module.
AllowEncodedSlashes can have a server default set with the apache class, and overridden with an apache::vhost declaration
Add the minimum required shibboleth declarations to directories hashes. Ignored if mod_shib not defined.