TabBar: use TabView.currentIndex
TabBar: use TabView.currentIndex

Change-Id: Idc8b7953b9707e6070ddc09880c5d85dbf10efed
Reviewed-by: Jens Bache-Wiig <9cea9d70b08f8210134ec5959114f72bad51ed1d@digia.com>

richardmg/qtcomponents,mizukusak/qtquickcontrols,drgvond/qtquickcontrols,kobolabs/qtquickcontrols,mizukusak/qtquickcontrols,drgvond/qtquickcontrols,kobolabs/qtquickcontrols,drgvond/qtquickcontrols,richardmg/qtcomponents,richardmg/qtcomponents,jfaust/qtquickcontrols,jfaust/qtquickcontrols,jfaust/qtquickcontrols,kobolabs/qtquickcontrols,mizukusak/qtquickcontrols