tor-spec: Change OR/OP to relay/client in some remaining places.
In combination with !283 and !286 (merged) this should take care of all of the usages of "OR" and "OP" in the "Tor Protocol Specification" section of the spec.
In combination with !283 and !286 (merged) this should take care of all of the usages of "OR" and "OP" in the "Tor Protocol Specification" section of the spec.