latest Kirigami master breaks header size assignments

[Dirk Hohndel]

Currently we do this:

Kirigami.ApplicationWindow {
	id: rootItem
	title: qsTr("Subsurface-mobile")

	header.minimumHeight: 0
	header.preferredHeight: Kirigami.Units.gridUnit * (Qt.platform.os == "ios" ? 2 : 1)
	header.maximumHeight: Kirigami.Units.gridUnit * 2 property bool fullscreen: true

But that fails with 
qrc:///qml/main.qml:15 Invalid grouped property access
(where line 15 is the header.minimumHeight: 0 assignement)

/D