check for blank email when rejecting a dupe

darcs-hash:20081202185343-5ed1f-99c314aac9e59ddbddd59ee403d4111c3639aa98.gz

actions/register.php

@@ -142,6 +142,9 @@ class RegisterAction extends Action {
 
 	function email_exists($email) {
 		$email = common_canonical_email($email);
+		if (!$email || strlen($email) == 0) {
+			return false;
+		}
 		$user = User::staticGet('email', $email);
 		return ($user !== false);
 	}