chutney: on failure, explain which connection failed
When there's a failure in the chutney data transmission tests, it would be really, really helpful to know which connection failed. The debug flag doesn't quite do this yet, but it's pretty close.
This is particularly important now that chutney supports three different types of connectivity tests (in the same network):
- client -> exit
- bridge client -> exit
- [bridge] client -> hidden service
Over two different protocols:
- IPv6 (currently bridges only)