Avoid creating an extra Hash object when no options were given

actionpack/lib/action_controller/metal/head.rb

@@ -18,18 +18,20 @@ module Head
     #   render
     #
     # See Rack::Utils::SYMBOL_TO_STATUS_CODE for a full list of valid +status+ symbols.
-    def head(status, options = {})
+    def head(status, options = nil)
       if status.is_a?(Hash)
         raise ArgumentError, "#{status.inspect} is not a valid value for `status`."
       end
 
       status ||= :ok
 
-      location = options.delete(:location)
-      content_type = options.delete(:content_type)
+      if options
+        location = options.delete(:location)
+        content_type = options.delete(:content_type)
 
-      options.each do |key, value|
-        headers[key.to_s.split(/[-_]/).each { |v| v[0] = v[0].upcase }.join("-")] = value.to_s
+        options.each do |key, value|
+          headers[key.to_s.split(/[-_]/).each { |v| v[0] = v[0].upcase }.join("-")] = value.to_s
+        end
       end
 
       self.status = status