ofed: fix warnings during libibverbs compilation

create_qp_handle_resp_common_cleanup should be void
__ibv_cleanup_wq should use wq->cond for cond destroy
both issues were overlooked in:
a687910 ('Cleanup pthread locks in ofed RDMA verbs')

Signed-off-by: Bartosz Sobczak <bartosz.sobczak@intel.com>
Signed-off-by: Eric Joyner <erj@FreeBSD.org>

Reviewed by: sean.lim@dell.com, vangyzen@, erj@
MFC after: 1 day
Sponsored by: Intel Corporation
Differential Revision: https://reviews.freebsd.org/D43491