Commit dialog can amend message only without affecting any files

By @ch3cooli on October 17, 2012 17:13 (imported from Google Code)

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Very often we make typo mistakes in commit message.
But when we discover that, the working directory already becomes dirty.
If we use commit dialog to amend, the files will be updated to the index.
But we only want to change the commit message in this case, not to update the index.

I suggest to add a checkbox "Amend Message Only".