ukernel: don't enforce thread lockers in remove vop

ukernel: don't enforce thread lockers in remove vop

we enforce locking by pid. when we are ukernel, MyPidXX is stupid.

don't bother.

Reviewed-on: http://gerrit.openafs.org/5597
Reviewed-by: Derrick Brashear <shadow@dementix.org>
Tested-by: Derrick Brashear <shadow@dementix.org>
(cherry picked from commit da9044cff966736bc064166a7136c94c0bfc1e5f)

Change-Id: I84ec39a8fd6367a0a832eb5c9d8a9727454b8948
Reviewed-on: http://gerrit.openafs.org/5701
Reviewed-by: Derrick Brashear <shadow@dementix.org>
Tested-by: Derrick Brashear <shadow@dementix.org>