LU-12899 build: rhel8 not install kernel-rpm-macros

LU-12899 build: rhel8 not install kernel-rpm-macros

On RHEL8 kmodtool and kernel_module_package_buildreqs are not
installed with kernel-devel.

kernel_module_package_buildreqs is defined in kernel-rpm-marcos.
If kernel-rpm-macros is not installed, the Lustre RPM build will
report:
"Dependency tokens must begin with alpha-numeric, '_' or '/':
BuildRequires: %kernel_module_package_buildreqs"

This patch helps the developer understanding the detailed
information for the required packages when kernel-rpm-macros is
not installed.

Signed-off-by: Qian Yingjin <qian@ddn.com>
Change-Id: Id9b855eeac97d780d9c572d306da3c3a1fa95ea6
Reviewed-on: https://review.whamcloud.com/36557
Tested-by: jenkins <devops@whamcloud.com>
Reviewed-by: Shaun Tancheff <stancheff@cray.com>
Reviewed-by: Jian Yu <yujian@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>