Windows: Detect if AFSCache is memory mapped to a new address

Windows: Detect if AFSCache is memory mapped to a new address

The Windows AFSCache paging file contains pointer addresses
that are only valid if the file is memory mapped at a specific
memory address.  If the file is mapped at a new address, the
pointer values will be invalid and the service will crash with
an invalid memory access.

Check for address consistency and force the cache to be rebuilt
if the consistency is lost.

LICENSE MIT

Change-Id: Ie7fb64659f808f09279445f47c2f1385be0a53f0
Reviewed-on: http://gerrit.openafs.org/2095
Reviewed-by: Rod Widdowson <rdw@steadingsoftware.com>
Reviewed-by: Jeffrey Altman <jaltman@openafs.org>
Tested-by: Jeffrey Altman <jaltman@openafs.org>