LU-6697 build: remove SRPM dependency from kernel version

LU-6697 build: remove SRPM dependency from kernel version

If machine don't have default kernel sources installed
the following error will be when you "make srpm".

error: line 144: Version required: Requires: kernel =
make: *** [srpm] Error 1

Change-Id: I1ab6cf1650e97b86ca5f25723bf7244e3ca08a03
Signed-off-by: Dmitry Eremin <dmitry.eremin@intel.com>
Reviewed-on: http://review.whamcloud.com/15181
Tested-by: Jenkins
Reviewed-by: Bob Glossman <bob.glossman@intel.com>
Reviewed-by: Patrick Farrell <paf@cray.com>
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>