Fixed bug with writing empty <header-contribution>s
Fixed bug with writing empty <header-contribution>s

git-svn-id: ac804e38dcddf5e42ac850d29d9218b7df6087b7@461278 13f79535-47bb-0310-9956-ffa450edef68

topicusonderwijs/wicket,topicusonderwijs/wicket,zwsong/wicket,klopfdreh/wicket,mosoft521/wicket,AlienQueen/wicket,AlienQueen/wicket,freiheit-com/wicket,klopfdreh/wicket,dashorst/wicket,mafulafunk/wicket,bitstorm/wicket,astrapi69/wicket,aldaris/wicket,topicusonderwijs/wicket,mosoft521/wicket,astrapi69/wicket,zwsong/wicket,apache/wicket,aldaris/wicket,astrapi69/wicket,bitstorm/wicket,Servoy/wicket,aldaris/wicket,selckin/wicket,klopfdreh/wicket,bitstorm/wicket,aldaris/wicket,zwsong/wicket,selckin/wicket,bitstorm/wicket,klopfdreh/wicket,Servoy/wicket,dashorst/wicket,apache/wicket,AlienQueen/wicket,mosoft521/wicket,Servoy/wicket,martin-g/wicket-osgi,martin-g/wicket-osgi,astrapi69/wicket,AlienQueen/wicket,Servoy/wicket,apache/wicket,bitstorm/wicket,freiheit-com/wicket,mosoft521/wicket,mosoft521/wicket,selckin/wicket,dashorst/wicket,freiheit-com/wicket,Servoy/wicket,martin-g/wicket-osgi,zwsong/wicket,klopfdreh/wicket,freiheit-com/wicket,mafulafunk/wicket,selckin/wicket,topicusonderwijs/wicket,AlienQueen/wicket,aldaris/wicket,selckin/wicket,mafulafunk/wicket,apache/wicket,freiheit-com/wicket,dashorst/wicket,apache/wicket,dashorst/wicket,topicusonderwijs/wicket