redhat: remove the openafs-kernel-version.sh script

redhat: remove the openafs-kernel-version.sh script

Commit ec706b21530240d7fb66bad2f08513eff8f7c335 (Remove Linux 2.4 compat
from RedHat packaging) removed the use of the script
openafs-kernel-version.sh, which was used in the linux 2.4 days to look
up the current kernel version.  Nowadays, we use the openafs-kmodtool
script to determine the kernel version.

Remove the unused openafs-kernel-version.sh script from the package
sources.

Change-Id: I6494812004f7b59c786ff670ff37c2fdc354f371
Reviewed-on: https://gerrit.openafs.org/12996
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Stephan Wiesand <stephan.wiesand@desy.de>
Reviewed-by: Benjamin Kaduk <kaduk@mit.edu>