Except that it wouldn't be rape in that case. Rape in most modern legal systems has a very well-defined, specific meaning which includes factors that contribute to the rapists intent and actions. While I am not an expert on Swedish or International Law, it doesn't seem logical that a progressive country like Sweden would allow such a claim to stand.
Also, please understand that I'm not saying that in this hypothetical case, that the person who was HIV+ was in the right. In some states in the US, sexual contact with someone without informing them of your HIV status (if you know or suspect you are HIV+) is a very serious crime.