openssl: fix documentation errors with perl 5.18.

OpenSSL 1.0.1e doesn't build with Perl 5.18+ because of problems in
OpenSSL's pod files.  Apply the patch found at https://bugs.archlinux.org/task/35868?getfile=10648
(originally from http://www.linuxfromscratch.org/patches/blfs/svn/openssl-1.0.1e-fix_pod_syntax-1.patch)
when Perl v5.18+ is detected.

I'm on the fence about the OHAI["os"] == linux check because I
don't actually know if any other operating systems are affected.
I'm leaving it in to minimize the possible impact of this patch.
If we get any bug reports for the same issue from other systems
in the future we can adjust or remove that check as needed.