- Fix a stupid bug introduced in 2.0.15 where we were unmapping the
  wrong inode in fs/ntfs/inode.c::ntfs_attr_iget().
- Convert $MFT/$BITMAP access to attribute inode API and remove all
  remnants of the ugly mftbmp address space and operations hack. This
  means we finally have only one readpage function as well as only one
  async io completion handler. Yey! The mft bitmap is now just an
  attribute inode and is accessed from vol->mftbmp_ino just as if it
  were a normal file. Fake inodes rule. (-: