Always register accessor properties

Otherwise if an Item gets created without the QtQuick module being
imported, the engine would fatal.

Change-Id: I441c7a61a60f07f2a7e3249253dea359d4ab1c35
Reviewed-by: Martin Jones <martin.jones@nokia.com>

src/quick/items/qquickitem.cpp

@@ -2290,6 +2290,9 @@ void QQuickItemPrivate::init(QQuickItem *parent)
 #endif
 
     Q_Q(QQuickItem);
+
+    registerAccessorProperties();
+
     baselineOffset.invalidate();
 
     if (parent) {