Sending `X-Digest` rather than `Digest` authentication header

[raboof]

We're sending an X-Digest authentication header rather than a Digest one.

That looks intentional, but the server (at least in my case) really does expect a Digest. What is the rationale behind this choice? Perhaps this should be made configurable?

[inorganik]

For the setup I was making requests against, X-Digest was the expected header. If the server you were making requests to expects Digest, than yes, it should be configurable