root: fix test code to follow new help behavior
root: fix test code to follow new help behavior

"lab help" and "lab --help" don't wraps "git --help" anymore, so the tests
must also follow the same pattern.

Signed-off-by: Bruno Meneguele <82c7731bc2625bcbab88bc571aee6631ba3f66f3@redhat.com>

zaquestion/lab,zaquestion/lab