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

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The acceptance tests are provided untested - apologies, I don't have an environment to run them in.