If a failure is not an issue you could change the Errormode.
This variable determines what action is to be taken by QlikView when an error is encountered during script execution.
By default ErrorMode=1 the script execution will halt and the user will be prompted for action (non-batch mode).
By setting ErrorMode=0 QlikView will simply ignore the failure and continue script execution at the next script statement.
By setting ErrorMode=2 QlikView will trigger an "Execution of script failed..." error message immediately on failure, without prompting the user for action beforehand.
If you would like to receive a error after a failed reload you could use a on post reload Alert (Ctrl+Shift+A in the document) to generate a mail on ScriptErrorCount>0, content can be created using the ScriptErrorList and ScriptErrorDetails
You can change the Status as you suggested, and the history will still reflect the failure for the record. My experience is that you have to restart only the Management Service to have the change reflected in the QMC.
I would be careful, but I think it's a fairly safe edit to make as you are only editing the one file associated with that task.