Windows: Only allow the local system account to speak to the redirector

When we get the IOCTL_AFS_INITIALIZE_CONTROL_DEVICE IOCTL we check to
see whether the calling process is the LOCAL_SYSTEM_SID (the one that
services run at if they are not running as a specified SID).  If we
are not then the initialize fails ACCESS_DENIED.

If the debug build ONLY, setting the AFS_DBG_DISABLE_SYSTEM_SID_CHECK
bit in OpenAFSDebugFlags circumvents this check, allowing interactive
debugging.

Existing code stops two processes (or even handles) from trying to
initialize the system.

Change-Id: I2ef8ca3a0df908acba38b435178d0509e96d6114
Reviewed-on: http://gerrit.openafs.org/8842
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Tested-by: Jeffrey Altman <jaltman@your-file-system.com>
Reviewed-by: Jeffrey Altman <jaltman@your-file-system.com>
(cherry picked from commit 5138c07abd076e0fa90d70a175a3a822fb127ef5)
Reviewed-on: http://gerrit.openafs.org/8885
Windows: Restrict the Service IOCTLS to the service process

When the service starts the system we save it's PID and when we see a
IOCTL_AFS_INITIALIZE_REDIRECTOR_DEVICE,
IOCTL_AFS_PROCESS_IRP_REQUEST, IOCTL_AFS_PROCESS_IRP_RESULT,
IOCTL_AFS_SYSNAME_NOTIFICATION or IOCTL_AFS_SYSNAME_NOTIFICATION
ioctl we check that the calling process has that PID.

Change-Id: Ie66676bba4b4e4d858979babe9c0af4c53ea0143
Reviewed-on: http://gerrit.openafs.org/8844
Reviewed-by: Rod Widdowson <rdw@steadingsoftware.com>
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Jeffrey Altman <jaltman@your-file-system.com>
(cherry picked from commit 3ee5e20170b4c42f6fccabaf70e28d14e35fae53)
Reviewed-on: http://gerrit.openafs.org/8886