With https://github.com/google/ko/pull/73 we can link the Git ref information
into images with:
```
ln -r -s .git/refs ./cmd/foo/kodata
```
If the changeset package gets a `ref: <ref>` entry, it attempts to read that
file from `KO_DATA_PATH` next, which lets the changeset work much more effectively.
* Some fixes to the spoof.go and exporter.go
While reviewing some other CL, I saw some avenues for improving
spoof.go, to log the URL that's being fetched, which would help in test
debugging and to use switch construct, rather than nested if's.
While testing the change, I noticed some shifty loggin from the
exporter, so I fixed that as well while I was there.
* Continuation of the previous cleanups.
* Fix the issues with formatting by executing a grep
* and fix compilation error
* lowercase error
* fix the newly changed unit test
Matt Moore
Victor Agababov
mattmoor-sockpuppet
Yanwei Guo