Add apache::conf_dir, use it instead of params.

This is another change needed to make the httpd24 Software Collection
work on RHELish boxes.

Fix mod_systemd on RHEL/CentOS 6.

Puppet < 3.0 does not have unless.

Try another fix for Puppet 2.7 / Facter 1.7.

Add README and tests for ::apache::conf_dir.
Apparently missed one of these in the conversion

Use Concat instead of File.
Merge pull request #831 from mhaskel/typo

Apparently missed one of these in the conversion
Merge pull request #821 from smerrill/feature/fix-remaining-rhel6-scl-issues

Finish SCL support for RHEL/CentOS 6
Allow for better $logroot management

This commit now allows you to set the directory permissions on the default
$logroot directory by exposing $logroot_mode in init.pp. It also adds a
$logroot_ensure parameter to apache::vhost that can toggle the creation of a
vhost's logroot resource.