Fix refs local marshalling

[Kubuxu]

Part of #2803

[whyrusleeping]

should make this a log.Errorf or a log.Warningf

[Kubuxu]

I think it isn't needed, it might be a left over from someone debugging something.
It got here when I was rearranging the code.

[whyrusleeping]

@RichardLitt this changes the API

[RichardLitt]

Thanks @whyrusleeping. See ipfs-inactive/http-api-spec#98.

[jbenet]

This is a breaking change, right? The summary in the changelog DOES NOT imply it:

• Fix NDJSON output of ipfs refs local. (@Kubuxu, Fix refs local marshalling #2812)

• I understand that this change was necessary to fix a problem, therefore needing to move to ndjson
• The old behavior may be desired by people who have implemented this. It should be possible to get the exact old behavior from the API with a flag in case bindings dont want to change all their code just yet. This can be considered deprecated and removable in the future.
• NEVER assume that "because nobody is reporting a problem that nobody is using it". Very wrong, very brittle, very fail. sad doge.

[jbenet]

The changelog should say something like:

• [BREAKING] Fix NDJSON output of ipfs refs local. (@Kubuxu, Fix refs local marshalling #2812)
  Breaking change necessary to correct buggy behavior. For the old output format, use ipfs refs local --some-option.

[Kubuxu]

You can get the old behaviour using text/plain as a type of http-api.
They change is invisible from the CLI.

I shouldn't have disregarded this.

[whyrusleeping]

Lets change the changelog to say:

• [BREAKING] Fix NDJSON output of ipfs refs local. (@Kubuxu, Fix refs local marshalling #2812)
  Breaking change necessary to correct buggy behavior. For the old output format, use ipfs refs local --enc=text.