As a general rule: fixing bugs in software isn't just about changing code, it's about cleaning up any crap the older (broken) code may have created. We don't have the luxury of an auto-mechanic who might replace a leaky oil valve and happily ignore all of the oil that car has already leaked all over the highway. When we fix bugs, we have a responsibility to go out and scrub up all that oil.
Ask yourself: does the oil valve still has a leak (somewhere)? Did you clean up all of the spilt oil? If you think the valve doesn't currently leak, then cleaning up the oil will be the end of it -- but if there is still a leak, at least cleaning up the oil will give you a clean road to spot any future oil spills.
(This rant comes from a comment I made to an existing "bug" at my company involving bad data in our DB, which one of my coworkers decided needed to be saved for posterity in our documentation on good software development practices (after fixing my typos of course). I figured I might as well share it here as well)