LU-16382 spec: Don't include Group: tags.

LU-16382 spec: Don't include Group: tags.

Fedora Project has deprecated group tags:
  https://fedoraproject.org/wiki/RPMGroups
  https://docs.fedoraproject.org/en-US/packaging-guidelines/#_tags_and_sections

The groups tags currently used are not recognised by SUSE.

So remove all the Group: tags - except one.

The %kernel_module_package macro for SUSE requires that a group
be given.

Test-Parameters: trivial
Signed-off-by: Mr NeilBrown <neilb@suse.de>
Change-Id: I6b7222200ea1a02319a703d64542dfb9780c048a
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/49364
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: jsimmons <jsimmons@infradead.org>
Reviewed-by: Jian Yu <yujian@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>