Update exploit checks

Progress group 1: Making sure these checks comply with the new
guidelines. Please read: "How to write a check() method" found in
the wiki.
Saving progress

Progress group 2: Making sure these checks comply with the new
guidelines. Please read: "How to write a check() method" found in
the wiki.
Saving progress

Progress group 3: Making sure these checks comply with the new
guidelines. Please read: "How to write a check() method" found in
the wiki.
Saving progress

Progress group 4: Making sure these checks comply with the new
guidelines. Please read: "How to write a check() method" found in
the wiki.
Saving progress
Progress
Oops, I broke this module
Add routine to check bad check codes
Update rspec for ms08_067 check

The original version doesn't return a check if the host is invalid,
looks like it was forgotten. The new version will return Unknown
instead.
Add support to scan a range of IPs for the check command

[SeeRM #8737] This allows the check command to scan multiple hosts.
Fix nil rhost
Throw Unknown if connection times out
Address nil
Change check code
Remove to_s inside #{}
Add module for CVE-2012-4554
Delete garbage comment
Add Drupal advisory as reference
Add check method
Clean code