Don't assign to an unused variable in test_cookie

This saves us a warnings

Author: herwinw

test/test_cookie.rb

@@ -68,7 +68,7 @@ def s.service(request, response)
   end
 
   def setup_http_server_option
-    option = {:Port => 0}
+    {:Port => 0}
   end
 
   def test_cookie