Fix impossible length for migration table id.

[ytetsuro]

Each pull request should address a single issue and have a meaningful title.

Description

id column is too long.

https://dev.mysql.com/doc/refman/5.6/en/integer-types.html

Checklist:

• Securely signed commits
• Component(s) with PHPdocs
• Unit testing, with >80% coverage
• User guide updated
• Conforms to style guide

---------Remove from here down in your description----------

Notes

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[MGatner]

I agree the constraint is a mistake (probably copy-paste error) but BIGINT seems overkill. I suppose migrations will never take much storage either way though.