Don't fail 920addTestcases if it doesn't find the test modules.

This allows us to build a sonic "test" image successfully (it's in
quotes because it's not a fully functional test image yet).

BUG=chromium:220368
TEST=build_image test for sonic and daisy, inspected build logs

Change-Id: Ic51ace9206e90428df3bc4cad929b94e81efa46a
Reviewed-on: https://gerrit.chromium.org/gerrit/57387
Tested-by: Darin Petkov <petkov@chromium.org>
Reviewed-by: Mike Frysinger <vapier@chromium.org>
Commit-Queue: Darin Petkov <petkov@chromium.org>
1 file changed