OWNERS: restrict core/important subdirs to domain experts

Changes to these subdirs are infrequent enough that we can reasonably
restrict approval to general ebuild/eclass experts.

BUG=None
TEST=None

Change-Id: I36d0de85a02b0502431a5c5a424ca4144d9bc1e1
Reviewed-on: https://chromium-review.googlesource.com/1661090
Tested-by: Mike Frysinger <vapier@chromium.org>
Commit-Ready: Mike Frysinger <vapier@chromium.org>
Legacy-Commit-Queue: Commit Bot <commit-bot@chromium.org>
Reviewed-by: Chris McDonald <cjmcdonald@chromium.org>
6 files changed