Windows: Redirector opens must set a valid FsContext

Windows: Redirector opens must set a valid FsContext

A successful open must have FileObject->FsContext set to a structure
with a valid/initialized FSRTL_ADVANCED_FCB_HEADER object.

Not having this breaks assumptions in the kernel.

Patchset edited by Jeffrey Altman <jaltman@your-file-system.com>

Change-Id: I70c9045bfa02c54074c015e6e871ead63efb6769
Reviewed-on: http://gerrit.openafs.org/6782
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Jeffrey Altman <jaltman@secure-endpoints.com>
Tested-by: Jeffrey Altman <jaltman@secure-endpoints.com>