Handle func tests of swift cluster that hide /info

If a swift cluster configures the proxy server to not accept
/info requests, just do the best we can, skipping tests as
necessary.

To that end, if cors mode is not known we also skip the test.

Change-Id: I34f296c8717e0baf24ae552a7e38f9354ee91974
Merge "Handle func tests of swift cluster that hide /info"