Authorize.net sending 2 receipts

There have been a bunch of concerns on the forums over the years because Authorize.net sends out receipts and CiviCRM sends out receipts

e.g
http://forum.civicrm.org/index.php?topic=6878.0

Authorize.net allows people to configure whether they want receipts to go out - but CiviCRM over-rides this. By removing the CiviCRM override we can return control to the users. I have tested this and receipts are sent or not according to settings in Authorize.net.

The only concern is that we would probably have to add a warning on upgrade or in the release blog - in case people want the receipts to go out but haven't turned it on.

— a/CRM/Core/Payment/AuthorizeNet.php
+++ b/CRM/Core/Payment/AuthorizeNet.php
@@ -55,7 +55,6 @@ class CRM_Core_Payment_AuthorizeNet extends CRM_Core_Payment {
$this->_setParam('paymentType', 'AIM');
$this->_setParam('md5Hash', $paymentProcessor['signature']);

• $this->_setParam('emailCustomer', 'TRUE');
  $this->_setParam('timestamp', time());
  srand(time());
  $this->_setParam('sequence', rand(1, 1000));
  @@ -338,7 +337,6 @@ class CRM_Core_Payment_AuthorizeNet extends CRM_Core_Payment
  $fields = array();
  $fields['x_login'] = $this->_getParam('apiLogin');
  $fields['x_tran_key'] = $this->_getParam('paymentKey');
• $fields['x_email_customer'] = $this->_getParam('emailCustomer');
  $fields['x_first_name'] = $this->_getParam('billing_first_name');
  $fields['x_last_name'] = $this->_getParam('billing_last_name');
  $fields['x_address'] = $this->_getParam('street_address');