autotest: Expect BadStatusLine from XMLRPC servers

It seems that something (perhaps the new Python version) is causing
partially online Python XMLRPC servers to return bad status lines, which
breaks how we start said servers.

TEST=Starting XMLRPC server in a test doesn't break with BadStatusLine.
BUG=None

Change-Id: I01caa848791e2223f4d9601b2b832f8d311a2b11
Reviewed-on: https://gerrit.chromium.org/gerrit/47694
Tested-by: Christopher Wiley <wiley@chromium.org>
Reviewed-by: Alex Miller <milleral@chromium.org>
Commit-Queue: Christopher Wiley <wiley@chromium.org>
1 file changed