[PATCH 3/5] mountmgr.sys: Add an ioctl to directly make volume queries.

[Erich E. Hoover]

This patch adds a new ioctl similar to
IOCTL_MOUNTMGR_QUERY_UNIX_DRIVE, but this version directly returns the
FILE_FS_*_INFORMATION from the mountmgr implementation instead of
returning properties of the mount point and relying on the caller to
interpret those properties correctly.

Best,
Erich