failed to compute piece commitment - blockstore: block not found

[en0ma]

Describe the bug
Given that during file uploads, identity CIDs are skipped, and so they are not looked up from the blockstore #215 - (has some relationship to this discussion here multiformats/cid#21)

When Estuary tries to compute commp at https://github.com/application-research/estuary/blob/master/replication.go#L2627, it is not aware they are not in the blockstore, and so it fails with errors like;

2022-07-12T17:15:12.789Z        ERROR   estuary estuary/replication.go:1389     failed to compute piece commitment for content 1: failed to generate piece commitment: error traversing node at "Links/7/Hash": could not load link "bafkqaaa": blockstore: block not found    {"app_version": "v0.1.3-8-g2e22f4d-dirty"}

bafkqaaa is an identity cid and will not be in the blockstore

To Reproduce
Steps to reproduce the behavior:

1. Run Estuary locally
2. Upload a car file with identity cid
3. Get it to generate commp
4. It will fail to get the block for the identity cid

Expected behavior
Commp should be calculated correctly on the Estuary side

Actual behavior
Commp fails to be calculated on the Estuary side. it fails with error

2022-07-12T17:15:12.789Z        ERROR   estuary estuary/replication.go:1389     failed to compute piece commitment for content 1: failed to generate piece commitment: error traversing node at "Links/7/Hash": could not load link "bafkqaaa": blockstore: block not found    {"app_version": "v0.1.3-8-g2e22f4d-dirty"}

[en0ma]

addressed in #470