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

Change-Id: I53fd99fb4436b2cce7a8473a1e188cf8fcdf19eb