VintfObjectTest: fix properties

On devices with ro.boot.product.hardware.sku defined,
DeviceManifestTest actually fetches the value, causing
the test to fail. Set-up mocks correctly.

Test: run vintf_object_test on b1c1
Bug: 121205339
Change-Id: Ib34e9266a53cdd27337dd2da65926157a82cba55
1 file changed