Add recipe to enable mod_version

Some poor unfortunate souls (read: this guy) need to manage configuration files across multiple Apache versions. Since some [configuration directives](http://httpd.apache.org/docs/2.4/upgrading.html) have changed from Apache 2.2 to 2.4, `<IfVersion>` is our now our trusted friend.

From the Apache documentation:

> This module is designed for the use in test suites and large networks which have to deal with different httpd versions and different configurations. It provides a new container -- `<IfVersion>`, which allows a flexible version checking including numeric comparisons and regular expressions.

Test Kitchen seems to be failing in Ubuntu 14.04 for unrelated reasons at the moment; 
```
serverspec os detected as: Ubuntu 14.04 [x86_64]       
       loading ubuntu/14.04
       
apache2::default
<snip>
 apache is listening on port 80       
  listening on port 80 is defined in /etc/apache2/ports.conf       
  /etc/apache2/apache2.conf is the config file dropped by the cookbook       
  the apache configuration has no syntax errors (FAILED - 1)
```
I'm happy to submit changes to the Test Kitchen test suite for this pull request if they're necessary.