pre-upload: fix public overlay checks

The new overlay checks were tested against private overlays only.
The file layout in the public overlays are different which broke
some assumptions.  Shuffle code around to support both.

BUG=chromium:386495
TEST=checked existing/bad layout.confs in src/overlays/ and src/private-overlays/

Change-Id: Iae63e7bd7d5eb88fa6ef8e146b9e5b9d133ecac1
Reviewed-on: https://chromium-review.googlesource.com/219051
Reviewed-by: Steve Fung <stevefung@chromium.org>
Tested-by: Mike Frysinger <vapier@chromium.org>
1 file changed