When triggering the checkregistration:confirmed message, do so through close...

When triggering the checkregistration:confirmed message, do so through close so that we teardown the controller.

This fixes the problem of adding multiple email addresses in the same dialog lifespan.

close #215

browserid/static/dialog/controllers/checkregistration_controller.js

@@ -80,7 +80,7 @@
               // enable button
               $('#continue_button').removeClass('disabled');
 
-              self.publish("checkregistration:confirmed");
+              self.close("checkregistration:confirmed");
             } else if (status === 'pending') {
               // try again, what else can we do?
               self.setupRegCheck();