LU-12824 o2ib: Record rc in debug log on startup failure

Since kiblnd_startup() return -ENETDOWN on failure, let's record the
rc value for the failure case in the debug log.

Cray-bug-id: LUS-7935
Test-Parameters: trivial
Signed-off-by: Chris Horn <hornc@cray.com>
Change-Id: Ied934642bc567b8d3f51293d7dd095d47ff134df
Reviewed-on: https://review.whamcloud.com/36325
Tested-by: jenkins <devops@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>