Add Fedora 18+ and Kerberized NFS4 support

[dmwarren]

Very nice module, thank you! These changes allow the module to really meet all our site's NFS needs.

New:

• Remove support for "redhat" in favour of "rhel/centos" and "fedora" in order to support for systemd and new NFS service names on Fedora
• Manage rpc.gssd, rpc.svcgssd on Red Hat systems (running/enabled/flags stored in /etc/sysconfig/nfs)
• Manage the Kerberos realm in /etc/idmapd.conf
• Manage /etc/idmapd.conf with ERB templates instead of augeas

[jhoblitt]

'fedora' is part of $::osfamily == "RedHat' and 'rhel' is not a valid $::operatingsystem. Why was this change needed? It looks like you've just copied the same code over and over for centos/fedora/rhel?

This patch does not update / breaks the spec tests.

[haraldsk]

Back from vacation!

There's a lot of good work in here, @dmwarren .

But as @jhoblitt stated the $osfamily stuff and tests need to be fixed before I can merge it.

[traylenator]

RHEL 7 if course similar, though different again.