Update AuthenticatedWebViewActivity.java

Added a check to see if you have internet connection to View Site action (if you don't, then clearView).
Added a check to see if you have internet connection on reload when in View Site.
To see what I mean, try this use case: 
- navigate somewhere in View Site with internet enabled; 
- then, disable and try to refresh (you get 404);
- enable your internet and try to refresh (you are redirected to login, which might look nasty).

My solution: display alert if you don't have internet; re-login if when you reload, if need be. This is useful when your internet connection is fluctuant :)

Note: I used clearView() instead of loadUrl('about:blank'), because on reload you lose your last url (you keep reloading 'about:blank').