This is a set of changes to support symlink protection detection.

In addition this fixes some detection of cagefs. This adds the capability
to detect vanilla redhat derivative distro protections as well as protections
provided by grsecurity and cloudlinux. This includes mod_ruid2 detection,
Apache level patch provided protections, and kernel level protections.
Merge branch 'symlink_prot' of https://github.com/cpdans/addon_securityadvisor