SAML2_HTTPRedirect: Fix warning with value-less paramtere.
SAML2_HTTPRedirect: Fix warning with value-less paramtere.

This patch fixes warnings from query strings like:

    http://.../endpoint.php?foo&bar=test

(Where the parameter "foo" doesn't have a value.)

git-svn-id: a243b28a2a52d65555a829a95c8c333076d39ae1@3197 44740490-163a-0410-bde0-09ae8108e29a

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