Fix AttributeError on recent PyQt4
Fix AttributeError on recent PyQt4

minesense/VisTrails,minesense/VisTrails,minesense/VisTrails,minesense/VisTrails,VisTrails/VisTrails,VisTrails/VisTrails,VisTrails/VisTrails,VisTrails/VisTrails,minesense/VisTrails,VisTrails/VisTrails