Save sha without original sha when to save in Hashed

[keiko713]

open-api will talk to api when to make a new deploy, which is the list of files and shas:

{ "index.html": "file_sha", "foo.jpg": "pointer_file_sha:original_file_sha", "bar.html": "file_sha2"}

then, api response the following as required (need to upload these shas to api):

["file_sha", "pointer_file_sha"]

so that open-api knows that it needs to upload files that have these shas (index.html and foo.jpg).

Previously, open-api wasn't able to upload "foo.jpg" because it didn't recognize "pointer_file_sha" is about "foo.jpg". This PR fixes it.

[bcomnes]

LGTM. Maybe have David or Bryce take a peek at this though to see if there is a better way to do this. It feels like we are hiding two different types in a single type, but I'm a typed language noob.