Go directly to the underlying env_logger crate, as pretty_env_logger
hasn't been updated in some time, and I'd like to be able to redirect
the log output to a file more directly, and that feature is in a newer
version of the env logger than pretty_env_logger was pulling in.
It looks like the debian 9 test failures with libssh are the
same underlying issue as https://github.com/wez/wezterm/issues/1262
Poking around in the debug output, and then spelunking through the code,
we can use the `pubkeyacceptedtypes` ssh config option to add the key
type to the list of keys. This doesn't appear to be a documented
option in the current versions of openssh.
I'm not 100% sure that this is right, but it's worth a shot.
