build_image: move getent/ldd to /usr/local for base images

This moves them to the dev-only-extras.tbz2 package which can be
installed on base images later on.  Dev & test images should be
the same before & after this change.

BUG=None
TEST=precq passes

Change-Id: I9cd2907b638893f661de69f8af277f5db86d5884
Reviewed-on: https://chromium-review.googlesource.com/1506014
Commit-Ready: ChromeOS CL Exonerator Bot <chromiumos-cl-exonerator@appspot.gserviceaccount.com>
Tested-by: Mike Frysinger <vapier@chromium.org>
Reviewed-by: Chris McDonald <cjmcdonald@chromium.org>
2 files changed