SAML2/SignedElementHelper: Fix getValidatingCertificates.
SAML2/SignedElementHelper: Fix getValidatingCertificates.

This function did not properly validate signatures containing multiple
certificates (as is typical for metadata with certificate chains. The
fix is to ignore exceptions during validation.

git-svn-id: a243b28a2a52d65555a829a95c8c333076d39ae1@2461 44740490-163a-0410-bde0-09ae8108e29a

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