Tor should log 1-based hop numbers

The control-spec says hops are 1-based, and we often log "first hop":

  If HOP=HopNum is specified, Tor will choose the HopNumth hop in the
  circuit as the exit node, rather than the last node in the circuit.
  Hops are 1-indexed; generally, it is not permitted to attach to hop 1.

But the following functions log 0-based hops:

• choose_good_middle_server
• onion_extend_cpath (which also logs a 1-based hop message as well)

We need to add 1 to the 0-based hop counts in these functions.

Credit to Xiaofan Li for discovering this issue.