Moved classes into the Metasploit3 space

I'm just worried about all those naked classes just hanging around in
the top namespace. This shouldn't impact functionality at all.

While most modules don't define their own classes (this is usually the
job of Msf::Exploit and Rex), I can't think of a reason why you
shouldn't (well, aside from reusability). And yet, very rarely do
modules do it. It's not unknown, though -- the drda.rb capture module
defines a bunch of Constants, and the
post/windows/gather/credentials/bulletproof_ftp.rb module defines some
more interesting things.

So, this should be okay, as long as things are defined in the context of
the Metasploit module proper.

modules/exploits/multi/http/rails_secret_deserialization.rb

@@ -7,6 +7,9 @@
 
 require 'msf/core'
 
+class Metasploit3 < Msf::Exploit::Remote
+	Rank = ExcellentRanking
+
 	#Helper Classes copy/paste from Rails4
 	class MessageVerifier
 
@@ -93,9 +96,6 @@ class KeyGenerator
 
 	end
 
-class Metasploit3 < Msf::Exploit::Remote
-	Rank = ExcellentRanking
-
 	include Msf::Exploit::CmdStagerTFTP
 	include Msf::Exploit::Remote::HttpClient