DAFS: Correct FSYNC_VOL_QUERY_VOP checks

DAFS: Correct FSYNC_VOL_QUERY_VOP checks

Check that the given partition matches the vp partition, and ensure
the vp is not in an exclusive state when we check the state.
Otherwise, we may return pending vol ops for a volume on a different
partition, or we may incorrectly return that there is no pending vol
op when in fact the volume does not exist at all.

Change-Id: I3e28c0b7b372360d181a3310eb1fb7fce223ae59
Reviewed-on: http://gerrit.openafs.org/4308
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Derrick Brashear <shadow@dementia.org>