Try to protect from StaleElementReferenceException in is_displayed

I noticed that this happened in last Jenkins build in `test_ldap_auth_and_roles.py`.

If the passed locator is retrievable multiple times (string, ...), it is tried multiple times. Ignored with WebElement, as it is already broken if it raises StaleElementException.
What I was asking was, is this what is happening.....that when we first hit the element it is Stale, but after a short period, it's ok?