debuginfod: Query debuginfod servers before printing response

[Mark Wielaard]

Hi Noah,

On Fri, Sep 17, 2021 at 01:38:50PM -0400, Noah Sanci via Elfutils-devel wrote: 
> Here is an updated patch, removing checks for http response headers
> which debuginfod is not guaranteed
> to respond with. These headers caused tests to fail despite receiving
> sufficient headers to confirm functionality.

Yes, this looks good. Just checking for Content-Length and the new
X-DEBUGINFOD- headers should be good enough.

Nice commit message. Please push.

Thanks,

Mark