[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
am: 7beb2d6bff

Change-Id: Ia7317a143b4a1abda460a62749ac28dc293599dd