If the element has no text, assert_text prints AssertionError: Element None has no text attribute

[Leo Arias]

A test is failing because it tries to assert the text of an element that is showing no text.
The failure is correct, but the error message is bad:

AssertionError: Element None has no text attribute

We should print the element instead of None.

real = _get_text(elem)
if real is None:
        msg = 'Element %r has no text attribute' % _get_text(elem)

Here we know that _get_text will return None, and we are still using it for the message.