I attended the Sweden-Saudi Arabia World Cup game in 1994. There was a group of about 20-30 die-hard Swedish fans (face paint, flags, etc.) a few rows up from where I was sitting. At one point in the game, they broke into a cheer that I thought sounded just like "Jonas Savimbi! (clap-clap, clap-clap, clap)". After about 3 rounds of this, my friend turned to me and asked "Are they chanting 'Jonas Savimbi'?" Anyway, I'm guessing that they weren't actually referring to the Angolan rebel leader. Does anyone know what were really saying and what it means?
I doubt it was some group of swedish pro-UNITA fans you and your friend had sitting behind you. From the description of the chant my guess is that they were shouting "Vi älskar sverige" (We love Sweden). The cheer is followed by the handclap you described and is a very common chant at Swedish national team matches.