LU-11647 ptlrpc: always unregister bulk

LU-11647 ptlrpc: always unregister bulk

In ptlrpc_check_set, the bulk should be unregistered before
ptl_send_rpc in any case.

Lustre-change: https://review.whamcloud.com/22378
Lustre-commit: e34a4cf031a2b83259cee8e05c2f646b5652b6a9

Change-Id: Icf963002f934b43ccbb9d6ef02ba7f9d11f297f8
Signed-off-by: Hongchao Zhang <hongchao@whamcloud.com>
Reviewed-on: https://review.whamcloud.com/33798
Tested-by: Jenkins
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Alex Zhuravlev <bzzz@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>