[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

Change-Id: Ib0eaf8802276444c611e51e2fd26a5b02c8651f6