station_based_test_list: properly override dut_options

We should override test_list.options.dut_options rather than
test_list.dut_options.

BUG=None
TEST=manual test

Change-Id: If6ac90b50dc048144befe56a6d0a2b5ac651baac
Reviewed-on: https://chromium-review.googlesource.com/350400
Commit-Ready: Wei-Han Chen <stimim@chromium.org>
Tested-by: Wei-Han Chen <stimim@chromium.org>
Reviewed-by: Hung-Te Lin <hungte@chromium.org>
1 file changed