remove "not public" error page

this is not used anymore:
* not logged in users are redirected to the login page
* logged in users see the normal 404 page

app/controllers/posts_controller.rb

@@ -9,14 +9,7 @@ class PostsController < ApplicationController
   respond_to :html, :mobile, :json, :xml
 
   rescue_from Diaspora::NonPublic do
-    if user_signed_in?
+    authenticate_user!
-      @code = "not-public"
-      respond_to do |format|
-        format.all { render template: "errors/not_public", status: 404, layout: "error_page" }
-      end
-    else
-      authenticate_user!
-    end
   end
 
   rescue_from Diaspora::NotMine do

app/views/errors/not_public.haml

@@ -1,10 +0,0 @@
--# Copyright (c) 2010-2012, Diaspora Inc. This file is
--# licensed under the Affero General Public License version 3 or later. See
--# the COPYRIGHT file.
-
-.transparent.big-number
-  404
-%h3
-  = t("error_messages.post_not_public_or_not_exist")
-%p
-  = t("error_messages.login_try_again", login_link: new_user_session_path).html_safe

config/locales/diaspora/en.yml

@@ -91,9 +91,6 @@ en:
     helper:
       invalid_fields: "Invalid fields"
       correct_the_following_errors_and_try_again: "Correct the following errors and try again."
-    post_not_public: "The post you are trying to view is not public!"
-    post_not_public_or_not_exist: "The post you are trying to view is not public, or does not exist!"
-    login_try_again: "Please <a href='%{login_link}'>login</a> and try again."
 
   admins:
     admin_bar:

features/step_definitions/message_steps.rb

@@ -5,8 +5,6 @@ Then /^I should see the "(.*)" message$/ do |message|
              I18n.translate('invitation_codes.excited', :name => @alice.name)
            when "welcome to diaspora"
              I18n.translate('users.getting_started.well_hello_there')
-           when 'post not public'
-             I18n.translate('error_messages.post_not_public_or_not_exist')
            else
              raise "muriel, you don't have that message key, add one here"
            end