chroot_version_hooks: refactor internal overlay structure

Several boards need to have their configuration regenerated.

BUG=None
TEST=None
CQ-DEPEND=CL:*253741
CQ-DEPEND=CL:*255709
CQ-DEPEND=CL:*255690
CQ-DEPEND=CL:*255712
CQ-DEPEND=CL:*255765
CQ-DEPEND=CL:*255713
CQ-DEPEND=CL:*255747
CQ-DEPEND=CL:*255737
CQ-DEPEND=CL:*255719
CQ-DEPEND=CL:*255748
CQ-DEPEND=CL:*255766
CQ-DEPEND=CL:*255691
CQ-DEPEND=CL:*255738
CQ-DEPEND=CL:*255721
CQ-DEPEND=CL:*255775

Change-Id: I52aae587a4d277d5a22741529ae61f4629764283
Reviewed-on: https://chromium-review.googlesource.com/339840
Commit-Ready: Bernie Thompson <bhthompson@chromium.org>
Tested-by: Bernie Thompson <bhthompson@chromium.org>
Reviewed-by: Mike Frysinger <vapier@chromium.org>
1 file changed