[DO NOT MERGE] Update security string to 2018-02-01 for mnc-dev bug:70348883 am: 74f105c16f am: 6545915c0b am: 567d926508 am: 06602d3239  -s ours am: 3980822dff am: 5d59b6650b am: ca5b4e7969
am: dc0deb3b47

Change-Id: I54ce4c9298722188ee2033e2bacdd2fed586ec52