Add constant for reverse check code lookup

lib/msf/core/exploit.rb

@@ -107,6 +107,14 @@ class Exploit < Msf::Module
     # The module does not support the check method.
     #
     Unsupported = [ 'unsupported', "This module does not support check." ]
+
+    #
+    # Hash for looking up codes by short name
+    #
+    Codes = [Unknown, Safe, Detected, Appears, Vulnerable, Unsupported].reduce({}) do |codes, code|
+      codes[code.first] = code
+      codes
+    end.freeze
   end
 
   #