[DO NOT MERGE] Updating Security String to 2017-09-01 Bug:63846344 am: 8d56fc91b1 am: 4b61de46b5 am: 73c3609c53 am: 08425ba495
am: 5aaced88b8  -s ours

Change-Id: I60f2772a3c751a6c4bc5fd352ede97bf1b77445b