overlays: Fix misnamed overlays.

Update repo_name in:
  overlay-amd64-corei7
  overlay-amd64-drm

BUG=chromium:889662
TEST=cros_mark_as_stable --dryrun

Change-Id: I355311d557ee4137de5d7795b01596ed84f8340d
Reviewed-on: https://chromium-review.googlesource.com/1255789
Tested-by: Mike Frysinger <vapier@chromium.org>
Reviewed-by: Don Garrett <dgarrett@chromium.org>
2 files changed