Hello,

I have a lot of repositories in my docker registry. lets say if have this tool:

package main

import (
	"fmt"
	"github.com/heroku/docker-registry-client/registry"
)

func main() {
	url := "https://testrepo.com/"
	username := "" // anonymous
	pass := ""
	hub, err := registry.New(url, username, pass)
	if err != nil {
		fmt.Print(err.Error())
	} else {
		repositories, err := hub.Repositories()
		if err != nil {
			fmt.Print(err.Error())
		}
		fmt.Printf("%v", repositories)
	}
}

When I run this, I get the following error:

Get /v2/_catalog?last=lastrepo&n=100: unsupported protocol scheme ""[]

From what I understand, the nextlink returned in the headers do not have the scheme and host part. I think that part should be kept somewhere in json.go so the getPaginatedJson method returns the full URL