[FixRM: #7535] Missing normalize() in OptPort

[FixRM: #7535] - Sometimes OptPort can return as a String instead of Fixnum because OptPort is missing the normalize() function.

Before the fix:

	>> active_module.options.validate(active_module.datastore)
	=> true
	>> active_module.datastore["RPORT"]
	=> "80"

After the fix:

	>> active_module.options.validate(active_module.datastore)
	=> true
	>> active_module.datastore["RPORT"]
	=> 6905
	>>

Ticket can be found here:
http://dev.metasploit.com/redmine/issues/7535