Fix #5462 - attempt to change email without login

Require an active login when accessing the form to change an email
address associated with an account. This prevents a server crash when
a user is assumed to be part of the request.

mediagoblin/edit/views.py

@@ -443,6 +443,7 @@ def verify_email(request):
         user=user.username)
 
 
+@require_active_login
 def change_email(request):
     """ View to change the user's email """
     form = forms.ChangeEmailForm(request.form)