clean old chromeos-base/chromeos-bsp-null

We are converting virtual/chromeos-bsp to a new style virtual, but we
have to clean out the old one first as it has a PROVIDE= which messes
up the upgrade process.

BUG=chromium-os:38307
TEST=`./update_chroot` uninstalled this pkg for all generic boards
CQ-DEPEND=CL:42188

Change-Id: Ie23bf462a178bf1085a4700155b779e9651ad24d
Reviewed-on: https://gerrit.chromium.org/gerrit/42528
Reviewed-by: Anush Elangovan <anush@google.com>
Commit-Queue: Mike Frysinger <vapier@chromium.org>
Tested-by: Mike Frysinger <vapier@chromium.org>
1 file changed