Windows: AFSInitFcb assign pFcb->ObjectInformation

Windows: AFSInitFcb assign pFcb->ObjectInformation

In AFSInitFcb() assign pFcb->ObjectInformation before the
InterlockedExchangePointer call and not afterwards.  Assigning
it afterwards leaves a small race where the ObjectInformation
value will be invalid.

Change-Id: Ie79587e0b2f161b7ff612fc4fb283135bafd1085
Reviewed-on: http://gerrit.openafs.org/8222
Reviewed-by: Rod Widdowson <rdw@steadingsoftware.com>
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Jeffrey Altman <jaltman@your-file-system.com>
Tested-by: Jeffrey Altman <jaltman@your-file-system.com>