Windows: fs getcacheparms

Windows: fs getcacheparms

The get cache params output is supposed to include two values:

 . the size of the cache

 . the size of the cache in use

Windows no longer has a concept of an unused cache buffer.  All
buffers are inserted onto the freelist and are available for
recycling when the AFSCache file is created.  Instead of reporting
the used cache space as 0K, report it as the full cache in use.
It is likely to disturb users less.

Change-Id: I6c1475f26e561d245bfa2b658c77ba683f735bb5
Reviewed-on: http://gerrit.openafs.org/7284
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Tested-by: Jeffrey Altman <jaltman@secure-endpoints.com>
Reviewed-by: Jeffrey Altman <jaltman@secure-endpoints.com>