Avoid crash for stss sync sample number 0 am: 5c364997a3 am: e77a32bd3d am: ab28d49e41  -s ours am: 73db408aa3 am: 0bb0a8e1e8 am: 4d86bef7f7 am: 241f5feb8a
am: a7cec6180f

Change-Id: I75a8ee185d28f82f6760a9b7d392161762e3399d