sys-libs/readline:  Remove from portage-stable.

This is the final step of moving sys-libs/readline from
portage-stable to chromiumos-overlay. The package has already
been committed in chromiumos-overlay.

BUG=None
TEST=None

Change-Id: Ic9e548fdde55c40ccc6ab7e3753fce25c37ccd9c
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/overlays/portage-stable/+/2525214
Auto-Submit: Caroline Tice <cmtice@chromium.org>
Reviewed-by: Manoj Gupta <manojgupta@chromium.org>
Tested-by: Manoj Gupta <manojgupta@chromium.org>
Commit-Queue: Manoj Gupta <manojgupta@chromium.org>
10 files changed