AttributeAlter: remove attributes when all their values are removed by the filter.
AttributeAlter: remove attributes when all their values are removed by the filter.

git-svn-id: a243b28a2a52d65555a829a95c8c333076d39ae1@3366 44740490-163a-0410-bde0-09ae8108e29a

madmatt/simplesamlphp,BrettMerrick/simplesamlphp,dzuelke/simplesamlphp,dialogik/simplesamlphp,madmatt/simplesamlphp,jschlyter/simplesamlphp,StudentLifeMarketingAndDesign/simplesamlphp,sitya/simplesamlphp,simplesamlphp/simplesamlphp,shoaibali/simplesamlphp,cwaldbieser/simplesamlphp,grnet/simplesamlphp,simplesamlphp/simplesamlphp,gtkrug/simplesamlphp,gtkrug/simplesamlphp,Kunstmaan/simplesamlphp,dzuelke/simplesamlphp,madmatt/simplesamlphp,sylvainmed/simplesamlphp,grnet/simplesamlphp,ghalse/simplesamlphp,sitya/simplesamlphp,ghalse/simplesamlphp,sitya/simplesamlphp,girgen/simplesamlphp,grnet/simplesamlphp,dialogik/simplesamlphp,dnmvisser/simplesamlphp,sylvainmed/simplesamlphp,StudentLifeMarketingAndDesign/simplesamlphp,Kunstmaan/simplesamlphp,dialogik/simplesamlphp,jschlyter/simplesamlphp,Kunstmaan/simplesamlphp,Kunstmaan/simplesamlphp,gtkrug/simplesamlphp,ghalse/simplesamlphp,jschlyter/simplesamlphp,sylvainmed/simplesamlphp,madmatt/simplesamlphp,sitya/simplesamlphp,cwaldbieser/simplesamlphp,jschlyter/simplesamlphp,girgen/simplesamlphp,dialogik/simplesamlphp,sylvainmed/simplesamlphp,maytechnet/simplesamlphp,dnmvisser/simplesamlphp,cwaldbieser/simplesamlphp,BrettMerrick/simplesamlphp,BrettMerrick/simplesamlphp,BrettMerrick/simplesamlphp,StudentLifeMarketingAndDesign/simplesamlphp,simplesamlphp/simplesamlphp,dzuelke/simplesamlphp,shoaibali/simplesamlphp,grnet/simplesamlphp,maytechnet/simplesamlphp,StudentLifeMarketingAndDesign/simplesamlphp,jschlyter/simplesamlphp,girgen/simplesamlphp,cwaldbieser/simplesamlphp,dnmvisser/simplesamlphp,girgen/simplesamlphp,dnmvisser/simplesamlphp,shoaibali/simplesamlphp,gtkrug/simplesamlphp,simplesamlphp/simplesamlphp,dzuelke/simplesamlphp,dialogik/simplesamlphp,maytechnet/simplesamlphp,shoaibali/simplesamlphp,girgen/simplesamlphp,ghalse/simplesamlphp,maytechnet/simplesamlphp