Starting on this now.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromiumos/overlays/board-overlays/+/ae94b9a2f9b9e3c9e51b5a37edf4b7ab84c7ad24

commit ae94b9a2f9b9e3c9e51b5a37edf4b7ab84c7ad24
Author: Jason D. Clinton <jclinton@chromium.org>
Date: Sun Dec 10 04:32:28 2017

Remove overlay-reef-uni

Reef is now unibuild so we are deleting this overlay.

BUG= chromium:788793 
TEST=none

Change-Id: I5af08c528f3895d3dbfdf38f6d5d300c822e3008
Reviewed-on: https://chromium-review.googlesource.com/817984
Commit-Ready: Jason Clinton <jclinton@chromium.org>
Tested-by: Jason Clinton <jclinton@chromium.org>
Reviewed-by: YH Lin <yueherngl@chromium.org>
Reviewed-by: C Shapiro <shapiroc@google.com>

[delete] https://crrev.com/5541814d9a6be5272023300cb44225fb118529aa/overlay-reef-uni/profiles/base/parent
[delete] https://crrev.com/5541814d9a6be5272023300cb44225fb118529aa/overlay-reef-uni/profiles/base/make.defaults
[delete] https://crrev.com/5541814d9a6be5272023300cb44225fb118529aa/overlay-reef-uni/toolchain.conf
[delete] https://crrev.com/5541814d9a6be5272023300cb44225fb118529aa/overlay-reef-uni/make.conf
[delete] https://crrev.com/5541814d9a6be5272023300cb44225fb118529aa/overlay-reef-uni/metadata/layout.conf
[delete] https://crrev.com/5541814d9a6be5272023300cb44225fb118529aa/overlay-reef-uni/chromeos-base/chromeos-bsp-reef-uni/chromeos-bsp-reef-uni-0.0.1-r1.ebuild
[delete] https://crrev.com/5541814d9a6be5272023300cb44225fb118529aa/overlay-reef-uni/chromeos-base/chromeos-bsp-reef-uni/chromeos-bsp-reef-uni-0.0.1.ebuild
[delete] https://crrev.com/5541814d9a6be5272023300cb44225fb118529aa/overlay-reef-uni/COMMIT-QUEUE.ini

The following revision refers to this bug:
  https://chrome-internal.googlesource.com/chromeos/manifest-internal/+/b1931c20ac23b3f08790474f75742eae6b6496b6

commit b1931c20ac23b3f08790474f75742eae6b6496b6
Author: Jason D. Clinton <jclinton@chromium.org>
Date: Mon Dec 11 20:47:49 2017