Fix broken tab rendering for TabView
Fix broken tab rendering for TabView

There was a missing change notification on the paintMargins
property. This was not caused, but simply triggered by the
change to v4.

Change-Id: Icf055d222bac39bd77cb4d3dc2f4c4c90ac629eb
Reviewed-by: J-P Nurmi <b84a892f57a298bb5dae653b4e188948a84d5549@digia.com>

drgvond/qtquickcontrols,kobolabs/qtquickcontrols,kobolabs/qtquickcontrols,mizukusak/qtquickcontrols,drgvond/qtquickcontrols,mizukusak/qtquickcontrols,drgvond/qtquickcontrols,mizukusak/qtquickcontrols,kobolabs/qtquickcontrols