Fix checkbox properties in TestBench
Fix checkbox properties in TestBench

Since the "result" will allways evaluate to true simply because
it is defined. We need to check if the string is "true" as well.

Change-Id: I53302d4a9a1ad9a11e474484339b63720b63ba4d
Reviewed-by: Jens Bache-Wiig <9cea9d70b08f8210134ec5959114f72bad51ed1d@digia.com>

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