RedHat: Munge future kernel versions

We currently look for "fc1?" (that is, fc10 through fc19) when trying
to munge the kernel version in some ways. This broke on Fedora 20,
since 20 obviously does not match "fc1?". Similarly, we look
specifically for "el6" for RHEL6 versioning quirks, but these will
break on RHEL7 and beyond.

Change the version checks so that this will work all the way through
Fedora 99 and RHEL 9. That won't work forever, but it will keep us
working for a few versions if the versioning quirks do not change.

Reviewed-on: http://gerrit.openafs.org/10618
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Derrick Brashear <shadow@your-file-system.com>
Reviewed-by: Ken Dreyer <ktdreyer@ktdreyer.com>
(cherry picked from commit cddc732ec5fd40c94126e5f0b7103136592a2efe)

Change-Id: I439cd3101ea360b775c638cd67961fc0e4ffcaf6
Reviewed-on: http://gerrit.openafs.org/10619
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Derrick Brashear <shadow@your-file-system.com>
Reviewed-by: Andrew Deason <adeason@sinenomine.net>
Reviewed-by: Michael Meffie <mmeffie@sinenomine.net>
Reviewed-by: Stephan Wiesand <stephan.wiesand@desy.de>