first pass at attempt_login for DB2

first pass through at the attempt_login method
for the DB2 LoginScanner. still adding specs
and possibly refactoring
Fix faulty spec
Merge pull request #19 from rapid7/feature/login_scanner/smb

Specs all passing, functional steps working.
working DB2 loginscanner

w00t
hacking on the pop3 login scanner

MSP-9678
Add better #inspect for Credential and Result
some minor cleanup

minor edits requested by kronicdeth during
code review
returning the result class

MSP-9678
derp
Merge branch 'staging/electro-release' into feature/MSP-9678/pop3-login-scanner
Make sure fail case is correct

`rand(1000)` would return 0 one in a thousand times, causing this test to
randomly fail at that interval
Merge pull request #17 from rapid7/feature/MSP-9606/metasploit-credential

Run migrations from Metasploit::Credential and initialize its concerns which patch Mdm
Merge branch 'master' into staging/electro-release
Merge branch 'staging/electro-release' into feature/MSP-9640/cred_creation

Conflicts:
	Gemfile.lock
Merge branch 'staging/electro-release' into feature/MSP-9686/vnc_login

MSP-9686
Merge branch 'feature/MSP-9686/vnc_login' into staging/electro-release

MSP-9686
Add WinRM login scanner

* Genericizes HTTP a bit to make these kinds of HTTP-based scanners
  simpler and easier
* Adds support for default ports to HTTP. This should probably be
  rafactored up into Base
* Removes spec that complains about port being unset (which now fails
  because defaults ensure it's always set)
Add specs for WinRM, improve those for HTTP
Drying up some of the status codes

MSP-9678
Merge remote-tracking branch 'upstream/master'