_run_ssh() of ssh.Exec doesn't pass throw=False to run_cmd(), which
makes it throw exceptions, and effectively strips the caller of any
chance to get hold of stdout and stderr. Pass throw=False and let
run() decide according the the caller-provided throw parameter
whether or not a problem should propagate up as exception or return
value.
Signed-off-by: Jan Lindemann <jan@janware.com>