DAFS: VnLock after VnWaitQuiescent in VAllocVnode

DAFS: VnLock after VnWaitQuiescent in VAllocVnode

In VAllocVnode, we write-lock the newly-allocated vnode. In DAFS,
however, we need to VnWaitQuiescent_r before VnLock'ing, since VnLock
in DAFS just sets the writer tid/pid. So, in VAllocVnode, move the
VnLock call to after we wait for quiescence, so we don't stomp over
the vnode when someone else has it write-locked.

Reviewed-on: http://gerrit.openafs.org/4059
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Michael Meffie <mmeffie@sinenomine.net>
Reviewed-by: Derrick Brashear <shadow@dementia.org>
(cherry picked from commit b41575d176c2d485d55aed8780bfab9db4b7587d)

Change-Id: I6c3d68f0f5248308d0f32e9fad5c540aaf593962
Reviewed-on: http://gerrit.openafs.org/4169
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Derrick Brashear <shadow@dementia.org>