staging/lustre/lnet: remove kiblnd_debug_conn/rx/tx

They are not called by anyone and cause gcc warning:
drivers/staging/lustre/lnet/klnds/o2iblnd/o2iblnd.c:609: warning: ‘kiblnd_debug_conn’
defined but not used
drivers/staging/lustre/lnet/klnds/o2iblnd/o2iblnd.c:589: warning: ‘kiblnd_debug_rx’
defined but not used
drivers/staging/lustre/lnet/klnds/o2iblnd/o2iblnd.c:597: warning: ‘kiblnd_debug_tx’
defined but not used

Cc: Andreas Dilger <andreas.dilger@intel.com>
Cc: Oleg Drokin <oleg.drokin@intel.com>
Signed-off-by: Peng Tao <bergwolf@gmail.com>