Windows: Redirector must query volume size when asked

Windows: Redirector must query volume size when asked

The volume size and free space cannot be obtained at volume
initialization and then re-used for all FileFsSizeInformation
and FileFsFullSizeInformation queries.  Doing so prevents Windows
from being able to see changes in the available free space.

The maximum size of the volume is not the size of the partition
and the available space on the partition unless there is no quota
applied to the volume.  If there is a quota, then the free space
is the smaller of the available quota and the available partition
space.

Add a new ioctl request to permit the redirector to query the
current Volume Size Information details.

Change-Id: I3414f314d7780fd12489e0d278b71bcadc1a72e6
Reviewed-on: http://gerrit.openafs.org/7052
Reviewed-by: Jeffrey Altman <jaltman@secure-endpoints.com>
Tested-by: Jeffrey Altman <jaltman@secure-endpoints.com>