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>
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>
(cherry picked from commit 0f9214164ad56bfe74d0f2cec8775a312f5128dd)

Change-Id: Ie414751cf01c44a73bf9eaef67c593cced2680d9
Reviewed-on: http://gerrit.openafs.org/6121
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Derrick Brashear <shadow@dementix.org>