MAGETWO-84000: Undefined index: region_id is presented after save customer address

Author: VladimirZaets

app/code/Magento/Customer/view/frontend/templates/widget/telephone.phtml

@@ -19,7 +19,7 @@
         <?php
             $_validationClass = $block->escapeHtmlAttr(
                 $this->helper('Magento\Customer\Helper\Address')
-                     ->getAttributeValidationClass('fax')
+                     ->getAttributeValidationClass('telephone')
             );
         ?>
         <input type="text"