don't use nullptr to stay compatible with !c++11 & qt4
don't use nullptr to stay compatible with !c++11 & qt4

Test Plan: Riddell shall test in production

Reviewers: dvratil, jriddell

Reviewed By: dvratil

Subscribers: anthonyfieroni

Differential Revision: https://phabricator.kde.org/D22378

KDE/phonon-gstreamer,KDE/phonon-gstreamer