cbuildbot: add lakitu and lakitu_next to nofactory_boards list

Two reasons for this change:
- both lakitu and lakitu_next do not use factory images
- chromium:613200 exposed a dependency between factory images and kernel
  configs: factory_netboot image requires CONFIG_USB_NET_DRIVERS must be
  enabled in the kernel.  Lakitu boards need neither.

TEST=Ran lakitu-incremental trybot (in addition to precq and paladin)
BUG=chromium:613200

Change-Id: Icba0a4f42139ce03c7749404d32b438e4ae3daa5
Reviewed-on: https://chromium-review.googlesource.com/350163
Commit-Ready: Amey Deshpande <ameyd@google.com>
Tested-by: Amey Deshpande <ameyd@google.com>
Reviewed-by: Aviv Keshet <akeshet@chromium.org>
2 files changed