Linux: 3: Update specfile to know about 3.* kernels.

Linux: 3: Update specfile to know about 3.* kernels.

Update spec file to be consistent with acinclude.m4 with regards to
sysnames.  We don't bother updating the code inside the legacy kernel
build section, as it doesn't get triggered for 3.* kernels (it should
probably get cleaned up at some point.)

Also, fix a bug in error message printing of unrecognized kernel.

Signed-off-by: Edward Z. Yang <ezyang@mit.edu>

Change-Id: Ife6046db0bec981be59aa053f63ae71458da7167
Reviewed-on: http://gerrit.openafs.org/6120
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Simon Wilkinson <sxw@inf.ed.ac.uk>
Reviewed-by: Derrick Brashear <shadow@dementix.org>