Fix object reference assignment E_NOTICE error

Author: carlbennett

src/controllers/User/Register.php

@@ -196,7 +196,7 @@ protected function tryRegister(Router &$router, UserRegisterModel &$model) {
       $mail = new PHPMailer( true ); // true enables exceptions
       $mail_config = Common::$config->email;
 
-      $state->mail &= $mail;
+      $state->mail = &$mail;
       $state->token = ( $user ? $user->getVerificationToken() : null );
       $state->user_id = $user_id;
 

src/controllers/User/ResetPassword.php

@@ -111,7 +111,7 @@ protected function doPasswordReset( UserResetPasswordModel &$model, &$data ) {
       $mail = new PHPMailer( true ); // true enables exceptions
       $mail_config = Common::$config->email;
 
-      $state->mail &= $mail;
+      $state->mail = &$mail;
       $state->token = $model->user->getVerificationToken();
       $state->user = $model->user;