Make email a required field. We're using the Kohana default error

messages when this fails, not the Gallery translation system so this
is not a great solution.  However, it's the same as the other
model-based rules we have currently so it's no worse.

Fixes ticket #897.

modules/user/models/user.php

@@ -23,7 +23,7 @@ class User_Model extends ORM implements User_Definition {
   var $rules = array(
     "name" => "required|length[1,32]",
     "full_name" => "length[0,255]",
-    "email" => "valid_email|length[1,255]",
+    "email" => "required|valid_email|length[1,255]",
     "password" => "length[1,40]",
     "url" => "valid_url",
     "locale" => "length[2,10]");