client: Update for FUSE access to parcel disk
client: Update for FUSE access to parcel disk

- No longer wait for udev in run() after launching PK

- No longer pass the DISK parameter to VMM drivers in run mode, since
the disk is now always at $CFGDIR/../vfs/image

- Shut down PK by lazy-unmounting the virtual filesystem rather than
by sending SIGTERM

cmusatyalab/openisr,cmusatyalab/openisr,cmusatyalab/openisr,cmusatyalab/openisr,cmusatyalab/openisr