Fix support for Apache 2.4 (debphp)
Move Scalr php settings after Apache

The Apache 2 SAPI will not exist if we have not yet installed Apache!
Reorder configuration
Don't rely on procps if you know the sysctl path
Standardize on value_for_platform_family
Add guards on selinux configuration
Ensure we configure rrdcached AFTER we install it!

Otherwise, we'll get a conflict.