If the information that we used to guess the payload type is part of the
payload, don't make it correspond to the "Payload Type" protocol tree
item - it's covered by the dissected payload.
If we don't succeed in guessing the protocol type, just dissect the
payload as data.
svn path=/trunk/; revision=13200
Use "guint16" instead of "u_int16_t", "guint8" instead of "u_int8_t",
and "guint" instead of "u_int", to handle platforms lacking the latter
types. Make "ppp_heuristic_guess()" reeturn a Boolean, as it just
returns a "yes or no" answer.
svn path=/trunk/; revision=13132