[DO NOT MERGE] Update Security String to 2017-04-01 on lmp-dev am: ffab69998a  -s ours am: 0f30aa9801 am: 05ebddebe5  -s ours
am: 101c043b17

Change-Id: Ia2e087b52c7bb4f3c8249d95d0b4b94bf9ba2a6c