There's no need to use the static UTS_RELEASE string, since
utsname()->release contains the same.

This avoids rebuilding this file for every change of the release string.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>