Record identified calls when one is missing

[ericclemmons]

Here's the scenario:

1. Today:
2. Get access token (recorded).
3. Get data with access token (recorded).
4. Tomorrow:
5. Get access token (replayed, same user).
6. Get data with access token fails because of 401.

The problem here is that we replay a fixture for that expired access token, but the new data calls need a valid token.

A couple ways to remedy this:

• The easiest way is that the normalizer should not delete any properties (e.g. sig, or possibly a date) that would replay old tokens for new requests.
• The harder way is to re-record all previously replayed requests that share that same identity. (However, what will this mean for previously-recorded responses that depend on those headers?)