[DO NOT MERGE] Update Security String to 2018-01-01 Bug : 69257226 am: 7da2c1c459  -s ours am: 2a81f8159f  -s ours am: e9e54c59aa
am: 81099d1dcb

Change-Id: Ia5bd95f347b19731ee2ad4bf101fea2f2cc8d27d