[tytso]

The problems with keeping the original commit and then putting the fixes on top are, (a) it makes the history harder to follow, (b) it makes it easy for someone to screw up a cherry-pick of a bug fix to a maintenance brance, since now you have to cherry-pick the bug fix plus the fix(es) to the bug fix, and (c) if the original patch had a potential bug that might cause the system to crash or otherwise malfunction, even if you fix it in the subsequent commit, it makes "git bisects" more likely to yield false positives, or at least make things more confusing and more difficult than it has to be.