Qt 5.0 beta requires changing the default to the 5.0 API, disabling
the deprecated code. However, tests should test (and often do) the
compatibility API too, so turn it back on.

Task-number: QTBUG-25053
Change-Id: Iab3d9fa844e74b7f8a17dbe1c26f9df6fa8dfadc
Reviewed-by: Olivier Goffart <ogoffart@woboq.com>