(cherry-pick of commit: 55c77504)

Bug: 37916906
Bug: 37896931
Test: none, just prebuilt update.
Change-Id: I55b5179f98703026699a59cce4b2e1afb166fd1d

More changes went into oc-dev after the freeze-date.  Reflect them.
(cherry-pick of commit: 148578a6)

Bug: 37916906
Bug: 37896931
Test: prebuilts - none.
Change-Id: I3300751ea7362d5d96b327138544be65eb9fc483

Copy the final system sepolicy from oc-dev to its prebuilt dir
corresponding to its version (26.0) so that we can uprev policy and
start maintaining compatibility files, as well as use it for CTS
tests targeting future platforms.

(cherry-pick of commit: 5c6a227e)

Bug: 37896931
Bug: 37916906
Test: none, this just copies the old policy.
Change-Id: Ib069d505e42595c467e5d1164fb16fcb0286ab93