LU-16207 build: add rpm-build BuildRequires for SLES15 SP3

LU-16207 build: add rpm-build BuildRequires for SLES15 SP3

SLES15 SP3 fails to build using rpm-build-4.14.1-29.46
from the main O/S repository with error message:

- Dependency tokens must begin with alpha-numeric,
  '_' or '/': BuildRequires: %kernel_module_package_buildreqs

Updating rpm-build to 4.14.3-150300.46.1 or higher
resolved the build issue.

Test-Parameters: trivial clientdistro=sles15sp3 \
testlist=sanity

Lustre-change: https://review.whamcloud.com/48760
Lustre-commit: 78c681d9f42cb56e30c8946e5d7b05f0bc6e86f2

Change-Id: I80099e7ba2d98e07b9877183879766f3dd7f3c1a
Signed-off-by: Jian Yu <yujian@whamcloud.com>
Reviewed-by: Colin Faber <cfaber@ddn.com>
Reviewed-by: Neil Brown <neilb@suse.de>
Reviewed-on: https://review.whamcloud.com/c/ex/lustre-release/+/49079
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>