Do minor clean up

Tries to clean a little bit the code on https://github.com/rapid7/metasploit-framework/pull/3179, I miss a little more of checking in the server answers, to verify if they are really alienvault legit answers. but not an stopper. On the other side, I couldn't verify I have not broken nothing because the original module wasn't working for me neither with the trial version! Please @brandonprry, verify I have not broken nothing! thanks!