In any case, it should either upgrade to 5.1, or leave 5.0, or ask which to use, or notify that there's a conflict and explain why. A smooth upgrade (as far as the user can tell) followed by a broken mysql which fails to start for no obvious reason (it's not apparent from the logs) is a bug in the upgrade process.
In any case, it should either upgrade to 5.1, or leave 5.0, or ask which to use, or notify that there's a conflict and explain why. A smooth upgrade (as far as the user can tell) followed by a broken mysql which fails to start for no obvious reason (it's not apparent from the logs) is a bug in the upgrade process.