Change OptPort to inherit from OptInt

Fixes the normalize and validate methods.

lib/msf/core/opt_port.rb

@@ -7,24 +7,13 @@ module Msf
 # Network port option.
 #
 ###
-class OptPort < OptBase
+class OptPort < OptInt
   def type
     return 'port'
   end
 
-  def normalize(value)
-    value.to_i
-  end
-
   def valid?(value)
-    return false if empty_required_value?(value)
-
-    if ((value != nil and value.to_s.empty? == false) and
-        ((value.to_s.match(/^\d+$/) == nil or value.to_i < 0 or value.to_i > 65535)))
-      return false
-    end
-
-    return super
+    super && normalize(value) <= 65535 && normalize(value) > 0
   end
 end