fix some qml warnings on dock removal

app/dockview.cpp

@@ -90,6 +90,7 @@ DockView::DockView(Plasma::Corona *corona, QScreen *targetScreen)
 DockView::~DockView()
 {
     qDebug() << "dock view deleting...";
+    rootContext()->setContextProperty(QStringLiteral("dock"), nullptr);
     this->disconnect();
     qDebug() << "dock view connections deleted...";
 
@@ -114,6 +115,7 @@ void DockView::init()
         updateFormFactor();
         syncGeometry();
     });
+
     rootContext()->setContextProperty(QStringLiteral("dock"), this);
     setSource(corona()->kPackage().filePath("lattedockui"));
     setVisible(true);

containment/contents/ui/VisibilityManager.qml

@@ -60,7 +60,7 @@ Item{
     property int thicknessZoomOriginal: statesLineSizeOriginal + ((plasmoid.configuration.iconSize+iconMarginOriginal) * root.zoomFactor) + 2
 
     Binding{
-        target: dock ? dock : manager
+        target: dock
         property:"maxThickness"
         when: dock
         value: thicknessZoomOriginal

containment/contents/ui/main.qml

@@ -529,7 +529,7 @@ DragDrop.DropArea {
     }
 
     Component.onDestruction: {
-        console.log("Destroying Now Dock Panel...");
+        console.log("Destroying Latte Dock Containment UI...");
     }
 
     Containment.onAppletAdded: {