portage-stable: remove app-portage/gentoolkit

gentoolkit has been imported in chromiumos-overlay and patched.

BUG=None
TEST=trybot run on chromiumos-sdk

CQ-DEPEND=CL:229676

Change-Id: Ia635a6aba65cbbf052cec32b6ebf867096a1b083
Reviewed-on: https://chromium-review.googlesource.com/229656
Reviewed-by: Mike Frysinger <vapier@chromium.org>
Commit-Queue: Bertrand Simonnet <bsimonnet@chromium.org>
Tested-by: Bertrand Simonnet <bsimonnet@chromium.org>
5 files changed