scons: move to packages feed

scons: move to packages feed

This patch removes scons host build tool, as commit 7087efd72a8d
("scons: move host build tool to a proper place") in the packages feed
has moved scons into the new home.

There are currently no packages in the master tree which would need
scons, yet scons is build always as part of host tools, just in order to
satisfy host build dependency of few packages in the packages feeds.

Ref: https://github.com/openwrt/packages/pull/9584
Acked-by: Hauke Mehrtens <hauke@hauke-m.de>
Signed-off-by: Petr Štetiar <ynezz@true.cz>