openafs.spec: Use /etc/openafs for configuration files

Previous commits uses a directory /etc/sysconfig/openafs instead of
/etc/openafs, which is in line with how Debian packages are built.  In
an attempt to keep things similar to debian, use /etc/openafs/ for
client configuration, and /etc/openafs/server/ for server
configuration.

Compatibility links are updated to reflect this change.
openafs-kmod: import openafs.spec from upstream project
openafs-kmod: Only build kernel module

I've removed everything related to the openafs project except for
building the kernel module.

Added to this is a new executable, find-installed-kversion.sh, which
uses the installed kernel headers to define the kversion, so the build
process no longer uses the output of `uname -r` or a --define
parameter to the rpmbuild command.  Instead, it parses
LINUX_VERSION_CODE and RHEL_RELEASE defined in <linux/version.h> and
builds the kversion from this.

Also, we're using the Red Hat kmodtool script instead of the OpenAFS
one.  It looks like this might make it easier to build dependencies
against kernel symbols instead of particular kernel releases.
find-installed-kversion.sh: make sure to output a define command
openafs-kmod.spec: add 'kernel' as a BuildRequires

The Red Hat rpmbuild automatic dependency generator uses the kernel's
symbols to add kernel symbol dependencies to the package.  For
example, if the kernel module uses vprintk(), it might use add this as
a dependency to the kmod package:

kernel(vprintk) = 0xbf8ba54a

To get access to the kernel symbols, the rpmbuild automatic dependency
generator needs the 'kernel' package installed.
Bumped version to 1.6.10
openafs-kmod.spec: switch to using upstream OpenAFS kmodtool script

Importing src/packaging/RedHat/openafs-kmodtool from
openafs-stable-1_6_10 in the OpenAFS git repo.
openafs-kmodtool: Add features from RH kmodtool

The Red Hat /usr/lib/rpm/redhat/kmodtool has the ability to add and
remove modules from weak-updates in the template RPM's pre and post
scripts.  This commit uses some of those mechanisms, adapting to the
environment available in the OpenAFS kmodtool script.