[DO NOT MERGE] Updating Security String to 2017-09-01 Bug:63846344 am: 4061effbfe am: e29d61d582 am: 775c752f51  -s ours am: 6399f470f6  -s ours
am: 4a126acfa7

Change-Id: Ic286a81fe536561739207c73178a44f7042b8430