Now, MPMs can be loaded at runtime and it's no longer required to compile in one
of the MPM modules statically. So, if version is >= 2.4, load the MPM module
corresponding to the multiProcessingModule value of the service module.
For details, please see: http://httpd.apache.org/docs/2.4/mpm.html
Signed-off-by: aszlig <aszlig@redmoonstudios.org>