Depends on country. If you have worked in a country with strong employee protection/rights/unions you have to mess it up quite badly to actually get "fired". That can be a serious hole in your application, if not outright immediately disqualifying you.

That's why there's versioning - to improve on the next generation. You improved.
Hurts? Yes. Necessary? Yes. No other option? Nope. Sometimes shit just suck? Yes. Did you do the right thing? Absolutely.
Pat on back. Re-compile and move on :)
Hope you feel better!