- add lo->lo_blocksize
 - kill lo_get_bs() - great name, but...
 - set ->lo_device only if we do have a block device
 - pull determination of ->lo_blocksize into both branches - bdev
   variant gets it from lo_device and file one uses ->i_blocksize.
 - switched the ioctl getting information about underlying object
   to lo->lo_device ? stat.rdev : stat.dev
 - i.e. st_rdev of underlying object if it's a device and st_dev - if it's
   a file.
 - reverted the bogosity in shmem.c