tor-resolve: Don't automatically refuse .onion addresses.

If the Tor is running with AutomapHostsOnResolve set, it _is_
reasonable to do a DNS lookup on a .onion address.  So instead we make
tor-resolve willing to try to resolve anything.  Only if Tor refuses
to resolve it do we suggest to the user that resolving a .onion
address may not work.

Fix for bug 1005.