broken updateBilling links on recur emails

CRM-12076 set updateBillingAddress links to only be added for some payment processors - but used the 'type' rather than the method used to determine whether the form will show (isSupported) leading to broken links in emails for processors that don't fit the box (e.g eWay)

Here is the determinant for allowing access to the link.
if (!$this->_paymentProcessorObj->isSupported('updateSubscriptionBillingInfo'))

{ CRM_Core_Error::fatal(ts("%1 processor doesn't support updating subscription billing details.", array(1 => $this->_paymentProcessorObj->_processorName) )); }