When an error is found parsing a playlist, stop
parsing. This will also prevent the emission of
the "loaded" signal when the parser finishes.
Task-number: QTBUG-40513
Change-Id: Ia814864d0d546806219993f0b727761d5d4e7903
Reviewed-by: Yoann Lopes <yoann.lopes@digia.com>
