404 page is rendered without content in TC Communities

[birdofpreyru]

When you visit an invalid endpoint inside some community, e.g. http://demo-expert.topcoder.com/404 a page is rendered with empty content. We should ensure, that a simple HTTP 404 Error message is shown. Note, that to see the problem, you should visit community using community-dedicated subdomain. If you access the same page as http://community-app.topcoder.com/community/demo-expert/fake-address you will be correctly redirected to HTTP 404 Page. However, in case of community accessed via subdomain, rather than such redirection, we would like just to add the error message to the page with community header and footer, already present when you visit http://demo-expert.topcoder.com/fake-address