- r16808,r16810,r16817,r16818,r16939: Don't send tunneled hidden service
directory requests to routers for which we don't have a
router descriptor. (Will significantly improve reliability.)
+ - r17091: distinguish "no routers support pending circuits" from
+ "no circuits are pending."
+ - r17137: send END cell in response to connect to nonexistent hidserv port.
+ - r17138: reject *:* servers should never do DNS lookups.
+ - r17139: Fix another case of overriding .exit choices.