Windows: Drop Fcb Resource across SetEOF and SetAllocation

Windows: Drop Fcb Resource across SetEOF and SetAllocation

If the file size or allocation is being altered, we must hold
the PagingResource and drop the Fcb Resource.  Dropping the
Fcb resource is necessary to avoid a deadlock with TrendMicro's
filter if the size is set to zero and acquiring the PagingResource
is necessary to prevent races now that the Fcb Resource is no
longer held.

Change-Id: Ie72a018adc52c479a4bb2469b2b1abe317644e8b
Reviewed-on: http://gerrit.openafs.org/7224
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Jeffrey Altman <jaltman@secure-endpoints.com>
Tested-by: Jeffrey Altman <jaltman@secure-endpoints.com>