erasure: Set fi.IsLatest when adding a new version

[krisis]

Description

This change sets fi.IsLatest to true whenever we add a new version under the namespace lock, like in PutObject, CopyObject and CompleteMultipartUpload. Previously, we would return FileInfo values with IsLatest not indicating current status. E.g bucket lifecycle policy evaluation wouldn't have the complete picture of this version.

Motivation and Context

This is required for features that may need current FileInfo state as seen by the object layer.

How to test this PR?

N/A

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Optimization (provides speedup with no functional changes)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• Fixes a regression (If yes, please add commit-id or PR # here)
• Documentation updated
• Unit tests added/updated

[minio-trusted]

Mint Automation

Test	Result
mint-large-bucket.sh	✔️
mint-fs.sh	✔️
mint-gateway-s3.sh	✔️
mint-erasure.sh	✔️
mint-dist-erasure.sh	✔️
mint-zoned.sh	✔️
mint-gateway-nas.sh	✔️
mint-compress-encrypt-dist-erasure.sh	✔️
Deleting image on docker hub
Deleting image locally

[vadmeste]

@krisis does this fix something or just for the future ?

[harshavardhana]

@krisis does this fix something or just for the future ?

@vadmeste this is precursor change for helping ComputeAction() do it's job for "immediate" transition feature.