devserver: correctly pass optional arguments to named build artifacts

BUG=chromium:294352
TEST=Unit tests

Change-Id: I7a75ee33d311fc51c21e716dae171fe641297c31
Reviewed-on: https://chromium-review.googlesource.com/169885
Tested-by: Gilad Arnold <garnold@chromium.org>
Reviewed-by: Chris Sosa <sosa@chromium.org>
Reviewed-by: Prashanth B <beeps@chromium.org>
Commit-Queue: Gilad Arnold <garnold@chromium.org>
1 file changed