LU-9306 kuc: initialize kkuc_groups at module init time

LU-9306 kuc: initialize kkuc_groups at module init time

Some kkuc functions use kkuc_groups[group].next == NULL to test for an
empty group list. This is incorrect if the group was previously added
to but not empty. Remove all next == NULL tests and use module load
time initialization of the kkuc_groups array.

Signed-off-by: John L. Hammond <john.hammond@intel.com>
Change-Id: I0d6af7b8584f18d1dc03873993d6aac55b1677a9
Reviewed-on: https://review.whamcloud.com/26883
Tested-by: Jenkins
Reviewed-by: Frank Zago <fzago@cray.com>
Reviewed-by: Faccini Bruno <bruno.faccini@intel.com>
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Henri Doreau <henri.doreau@cea.fr>
Reviewed-by: Quentin Bouget <quentin.bouget@cea.fr>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>