hash72: if the device has no UUID, use firewire ID
hash72: if the device has no UUID, use firewire ID

The nano5g uses a hash72 in its cbk file but doesn't have a 20 byte-long
uuid.  On these device, use the FirewireID instead padded with 0 to
calculate the hash72.

hyperair/libgpod,neuschaefer/libgpod,hyperair/libgpod,neuschaefer/libgpod,hyperair/libgpod,hyperair/libgpod,neuschaefer/libgpod,neuschaefer/libgpod,neuschaefer/libgpod,hyperair/libgpod