Fix QApplication::startDragDistance()

Change-Id: I1b95e25892935b2b6287b8fed719479e37dbcad5
Reviewed-on: http://codereview.qt-project.org/5308
Reviewed-by: Qt Sanity Bot <qt_sanity_bot@ovi.com>
Reviewed-by: Samuel Rødal <samuel.rodal@nokia.com>

src/widgets/kernel/qapplication.cpp

@@ -3449,7 +3449,7 @@ void QApplication::setStartDragDistance(int l)
 
 int QApplication::startDragDistance()
 {
-    return qApp->styleHints()->startDragTime();
+    return qApp->styleHints()->startDragDistance();
 }
 
 /*!