No output from ssh problems during bootstrap

Part of the bootstrap process is to ssh into the state server and finish setting it up. However, if there are ssh issues of any kind we commonly get something like this:

Waiting for address
Attempting to connect to 52.7.223.15:22
Attempting to connect to 172.31.7.58:22
2015-07-22 23:24:57 ERROR juju.cmd supercommand.go:429 failed to bootstrap environment: waited for 10m0s without being able to connect: ssh: connect to host 172.31.7.58 port 22: Connection timed out

Where juju just hangs for 10 minutes then gives up. There is no output saying what went wrong trying to connect, it can be using the wrong key, having known hosts issues, juju does not elaborate.

Really we want to know what the ssh output was if any, and to know what key juju was trying to connect with.