Add the 'guest' IPMI user

The 'guest' IPMI user exists on many Cisco Unified Computing Server (UCS) implementations.
Revert "Add initial firefox xpi prompt bypass."

This reverts commit ebcf972c08857ac946cea090bba520bb70bd2485.
Add exploit for CVE-2014-5005
Refactor if statement to early return

This eliminates the protracted if statement and aligns the code body.
Change module filename
Minor cleaning on check
Land #3741, @pedrib's module for CVE-2014-5005 Desktop Central file upload
Land #3736 - Revert initial ff xpi prompt bypass for Firefox 22-27
delete parenthesis
Land #3750, @wvu favoring unless
Land #3733, "guest" for ipmi_users.txt