[DO NOT MERGE] Update Security String to 2018-01-01 Bug : 69257226 am: 7da2c1c459  -s ours am: 2a81f8159f  -s ours am: e9e54c59aa am: 81099d1dcb
am: 7d4d9a50d8

Change-Id: Ic457f5ae443c68d83d7c5bf78d4475625a90d184