prevent lang in url when config.translate is false

This helps issue Apipie#549
Apipie#549

Author: markmoser

app/controllers/apipie/apipies_controller.rb

@@ -79,6 +79,7 @@ def apipie_checksum
     helper_method :heading
 
     def get_language
+      return nil unless Apipie.configuration.translate
       lang = Apipie.configuration.default_locale
       [:resource, :method, :version].each do |par|
         if params[par]