Write patch to make socks handshakes succeed instantly

In legacy/trac#3875 (moved) Mike suggests we try out the usability of having the Tor in TBB just immediately succeed at all socks handshakes, and hang up if it gets an end cell rather than a connected cell.

We should whip up a Tor patch that does this behavior, so somebody can try it out.

(We may or may not want to merge it into mainline Tor branches. I guess it depends how complex the patch is and how successful the tests are.)