Add tests for fetching over http instead of just https

[blixtra]

Currently we only test fetching over https connections. We should add some functional tests for http as well.

Related, what should be the behavior if insecure-options=tls is specified?

[alban]

Maybe we need a new --insecure-options=http option to support downloads when the discovery protocol returns a http:// URL.

[iaguis]

Maybe we need a new --insecure-options=http option to support downloads when the discovery protocol returns a http:// URL.

Isn't that what --insecure-options=tls is supposed to do?

[krnowak]

@iaguis: tls skips TLS certificate checks, but it still downloads over HTTPS.

There are two new options to consider - whether to allow downloading over HTTP and whether to allow sending credentials over HTTP.

[krnowak]

I think this will need some work on appc spec side - appc/spec#545

[iaguis]

Now that #1945 and appc/spec#551 are merged, do we have everything we need to start implementing this?

[krnowak]

Yeah, merge #1977 first. :P It has some work on a test aci server (so we can make it to accept HTTP connections instead of HTTPS) instead of downloading images from remote locations and thus making TestFetch even more unreliable.

[alban]

Depends on #1977 => update priority and milestone.

Do we still need the "dependency appc/spec"? appc/spec#551 was merged in spec 0.7.4 (included in rkt) and appc/spec#545 was closed.