devserver: fix a bug with __init__ keyword arguments

BUG=None
TEST=downloader_unittest.py passes.

Change-Id: I7bf650b0460e00f6c981781328dd90c65a6ee325
Reviewed-on: https://chromium-review.googlesource.com/176908
Tested-by: Gilad Arnold <garnold@chromium.org>
Reviewed-by: Chris Sosa <sosa@chromium.org>
1 file changed