stdout_hook returns without user/host information

The exception_hook is called with the user & hostname passed to it -- thats useful when working with a Rye::Set.

'cmd_clean' isn't exposed in the create_channel method, so this is the simplest way I could think to bring some uniformity to the callbacks.
Change SSH server in auth methods test
Bumped up sysinfo dep to 0.8.1
Version bump (0.9.12)