Review AlienVault OSSIM SQLi module

Hi @xistence, 

This pull request tries to clean https://github.com/rapid7/metasploit-framework/pull/3306, some style things and small fixes. 

Please, feel free to check to ensure I didn't break nothing. Once you're also able to test and feel comfortable with the changes, land this pull request and the original one https://github.com/rapid7/metasploit-framework/pull/3306 will be automatically updated.

Thanks!