[factory_test_tools] add OWNERS

TEST=none
BUG=chromium-os:22007

Change-Id: I68555c0f3b570ef12f8aacc17eb4bf4867999766
Reviewed-on: https://gerrit.chromium.org/gerrit/19806
Reviewed-by: Tammo Spalink <tammo@chromium.org>
Tested-by: Hung-Te Lin <hungte@chromium.org>
Commit-Ready: Hung-Te Lin <hungte@chromium.org>
1 file changed