QPainter: drop a pointless check

There's no need to check for nullptr before invoking delete.

Change-Id: Ied751f76f15f390bf86bbba53c14a3e450aa81e8
Reviewed-by: Gunnar Sletta <gunnar@sletta.org>

src/gui/painting/qpainter.cpp

@@ -209,9 +209,7 @@ QPainterPrivate::~QPainterPrivate()
 {
     delete emulationEngine;
     qDeleteAll(states);
-
-    if (dummyState)
-        delete dummyState;
+    delete dummyState;
 }