Move hwids back to portage-stable

Instead of modifying the ebuild, use the INSTALL_MASK to leave out
the compressed hwids databases.  So move hwids back to portage-stable.

CQ-DEPEND=I19c436c336fb9bf8b522d9c4836a305bc358214c
BUG=chromium:378950
TEST=panther image contains hwids database

Change-Id: Id24263360f1b9b69ed50e5d501bf1057382c88ad
Reviewed-on: https://chromium-review.googlesource.com/211280
Reviewed-by: Mike Frysinger <vapier@chromium.org>
Tested-by: Steve Fung <stevefung@chromium.org>
Commit-Queue: Steve Fung <stevefung@chromium.org>
4 files changed