Checking out over https fails

[dsvensson]

When trying to checkout https://gopkg.in/yaml.v2

I get the following error message:
pkt-line 3: invalid capabilities: arguments not allowed (symref=HEAD:refs/heads/v2 multi_ack thin-pack side-band side-band-64k ofs-delta shallow deepen-since deepen-not deepen-relative no-progress include-tag multi_ack_detailed no-done oldref=HEAD:refs/heads/v2 agent=git/github-g09a9ed6d3a)

The following code is used:

storer := memory.NewStorage()
repo, err := git.Clone(storer, nil, &git.CloneOptions{URL: "https://gopkg.in/yaml.v2"})
if err != nil {
    fmt.Println(err)
}

[orirawlings]

I suspect this is due to a bug in the validation code for capabilities (see (*capability.List).validate). Basically if an capability option isn't recognized, the code automatically assumes that it shouldn't allow arguments. I think in this case, go-git isn't familiar with the oldref option, and produces and error on the unexpected argument.

I'll work on a patch.