Swarm: infinite loading loop and incorrect merge check

Scenario

• Migrate an account
• Do a merge commit right after this

Expected

The repository should have correct informations

Current result

The repository is malformed and causes infinite loading messages loop

Detected problems

• LRC should not call loadingMessages in loop in case of an error
• we should check the author of the merge commit
• we should never create a merge commit after a migration without adding the certificate