Fix intended assignment to customSet variable.

The naming suggests that this variable should be set to true here (instead of leaving the expression result unused). Also, the variable isn't written to anywhere else.

Change-Id: I8aae904f6e4456ce0bdd053ce89c2721168dccd3
Reviewed-by: Laszlo Papp <lpapp@kde.org>
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@nokia.com>

src/gui/kernel/qplatformdialoghelper.cpp

@@ -310,7 +310,7 @@ void QColorDialogOptions::setCustomColor(int index, QRgb color)
 {
     if (uint(index) >= uint(QColorDialogStaticData::CustomColorCount))
         return;
-    qColorDialogStaticData()->customSet;
+    qColorDialogStaticData()->customSet = true;
     qColorDialogStaticData()->customRgb[index] = color;
 }