[rbridge] Hop Count processing

[James Carlson]

Radia Perlman writes:
> I suspect nobody will care, so we can just go with Dinesh's wording.

With the detailed rationale for the change, I'm happy enough with his
wording and the extra check on entry.

-- 
James Carlson, Solaris Networking              <james.d.carlson at sun.com>
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