chutney does not fail on some SOCKS errors

When tor can't make a connection, and sends back a SOCKS error, chutney keeps on rapidly sending SOCKS requests. Instead, chutney should fail.

I think we introduced this bug when we started using asyncore.

I have worked around the bug using a 5 second asyncore timeout, but we should come up with a permanent fix.

I think nickm might be able to help with this issue, because he wrote that code.