In devicemanager.cpp m_backend has to be checked always before dereferencing.
In devicemanager.cpp m_backend has to be checked always before
dereferencing.

Thanks to Erik Hovland

svn path=/trunk/kdesupport/phonon/; revision=891310

sandsmark/phonon-visualization-gsoc,sandsmark/phonon-visualization-gsoc,sandsmark/phonon-visualization-gsoc,sandsmark/phonon-visualization-gsoc