remove useless to_param call

extract_subdomain always returns a string, and to_param calls to_s on a
string

Author: tenderlove

actionpack/lib/action_dispatch/http/url.rb

@@ -126,7 +126,7 @@ def normalize_host(_host, options)
           if subdomain == true || !options.key?(:subdomain)
             return _host if options[:domain].nil?
 
-            host << extract_subdomain(_host, tld_length).to_param
+            host << extract_subdomain(_host, tld_length)
           elsif subdomain
             host << subdomain.to_param
           end