the SAME_RDEV bit into the next 8 bits and adding an EXTENDED_FLAG
bit.  Also modified the meaning of this bit for protocol 28 and above:
SAME_HIGH_RDEV indicates that all but the lowest byte matches.  The
older protocols get OLD_SAME_RDEV set (with the old semantics) for
compatibility.  Note also that protocol 28 isn't turned on yet.