MDL-40690 behat: Ignore StaleElementReference exception

Is another of the exceptions thrown by
Selenium when it tries to interact with
an element that disappeared from the DOM,
in happens randomly when redirecting the
user to another page with a wait period to
show him/her a message.

lib/tests/behat/behat_general.php

@@ -30,7 +30,8 @@ require_once(__DIR__ . '/../../behat/behat_base.php');
 use Behat\Mink\Exception\ExpectationException as ExpectationException,
     Behat\Mink\Exception\ElementNotFoundException as ElementNotFoundException,
     Behat\Mink\Exception\DriverException as DriverException,
-    WebDriver\Exception\NoSuchElement as NoSuchElement;
+    WebDriver\Exception\NoSuchElement as NoSuchElement,
+    WebDriver\Exception\StaleElementReference as StaleElementReference;
 
 /**
  * Cross component steps definitions.
@@ -84,6 +85,8 @@ class behat_general extends behat_base {
             $content = $metarefresh->getAttribute('content');
         } catch (NoSuchElement $e) {
             return false;
+        } catch (StaleElementReference $e) {
+            return false;
         }
 
         // Getting the refresh time and the url if present.