Try to ignore migration errors

[msm-cert]

Your checklist for this pull request

• [x] I've read the contributing guideline.
• [x] I've tested my changes by building and running mquery, and testing changed functionality (if applicable)
• [ ] I've added automated tests for my change (if applicable, optional)
• [ ] I've updated documentation to reflect my change (if applicable)

What is the current behaviour? On migration error process dies because of unhandled exception and becomes a zombie

What is the new behaviour? On migration error a clear error is logged, and process tries to keep going.