Allow override of device asserts, including multi-device support.

Set in board file with TARGET_OTA_ASSERT_DEVICE.
(cherry-picked from commit 0f452f21fc9323b9d1fe746161761cf40aaa5030)

Change-Id: I3d06bdc0e3e26bde0c0e646accd050364f9713b9
Note that update-api is a lie.

Change-Id: Idc2d92630e94ccbd60b5d5447c3762db8e5096f8
cm: Fix global selinux policy inclusion

We're adding slim-specific policies to an overlay instead of patching
external/sepolicy, so we need to make sure it's included to prevent
misbehaving systems

Change-Id: I7989a1093f9abc8360d492e73a860eb4afad10ad
Screw that too!