change render nothing calls to head ok

app/controllers/application_controller.rb

@@ -111,7 +111,7 @@ class ApplicationController < ActionController::Base
       flash[:notice] = "This feature isn't available: #{@exception.message}"
       respond_to do |fmt|
         fmt.html { redirect_back fallback_location: root_path }
-        fmt.js { render nothing: true, status: 501 }
+        fmt.js { head 501 }
         fmt.json { render template: "static/error", status: 501 }
         fmt.xml  { render template: "static/error", status: 501 }
       end

app/controllers/related_tags_controller.rb

@@ -17,7 +17,6 @@ class RelatedTagsController < ApplicationController
     @tag.related_tags = params[:related_tags]
     @tag.related_tags_updated_at = Time.now
     @tag.save
-
-    render nothing: true
+    head :ok
   end
 end