Replace lavabit example with riseup on FF 31 (Closes: #7972 and #7228)

wiki/src/doc/anonymous_internet/Tor_Browser.mdwn

@@ -27,20 +27,15 @@ with. But those mechanisms can be flawed,
 [[as explained on our warning page|about/warning#man-in-the-middle]].
 
 For example, here is how the browser looks like when we try to log in an email
-account at [lavabit.com](http://lavabit.com/), using their [webmail
-interface](https://lavabit.com/apps/webmail/src/login.php):
+account at [riseup.net](https://riseup.net/), using their [webmail
+interface](https://mail.riseup.net/):
 
-[[!img doc/anonymous_internet/Tor_Browser/lavabit.png link=no alt="Tor browser"]]
+[[!img doc/anonymous_internet/Tor_Browser/riseup.png link=no alt="Tor browser"]]
 
-Notice the small area on the left of the address bar saying "lavabit.com" on a
-blue background and the address beginning with "https://" (instead of
-"http://"):
-
-[[!img Tor_Browser/address-bar.png link=no alt="address bar showing 'lavabit.com'
-/ 'https://lavabit.com/'"]]
-
-These are the indicators that an encrypted connection using [[!wikipedia HTTPS]]
-is being used.
+Notice the padlock icon on the left of the address bar saying "mail.riseup.net"
+and the address beginning with "https://" (instead of "http://"). These are the
+indicators that an encrypted connection using [[!wikipedia HTTPS]] is being
+used.
 
 You should try to only use services providing HTTPS when you are sending or
 retrieving sensitive information (like passwords), otherwise its very easy for