[DO NOT MERGE] Update Security String to 2017-04-05 for mnc-dev am: af15999c69 am: f23c50fe08 am: ed7c7adb7e am: 46594018ce  -s ours am: acc43b9d4d am: cb57c6426e am: 5db0a5f30d  -s ours
am: 9b41b3f0f0  -s ours

Change-Id: If72c855446b0fe94cac5a4858460f1a502924d27