Change `failed to lookup index for mh` message to clarify it is a dagstore/local issue

[masih]

Checklist

• This is not a question or a support request. If you have any boost related questions, please ask in the discussion forum.
• This is not a new feature request. If it is, please file a feature request instead.
• I have searched on the issue tracker and the discussion forum, and there is no existing related issue or discussion.
• I am running the Latest release, or the most recent RC(release canadiate) for the upcoming release or the dev branch(master), or have an issue updating to any of these.

Boost component

• boost daemon - storage providers
• boost client
• boost UI
• boost data-transfer
• boost index-provider
• Other

Improvement Suggestion

This error is coming from local DagStore where the provider can't find piece information associated to a CID. It is not related to content discovery via IPNI.

It would be great to change failed to lookup index for mh to something else in order to avoid confusion with IPNI lookup issue.