[cddlm] new invalid test: extends and default xmlns

[Steve Loughran]

There's a new invalid test soon to appear under invalid/set-01, one that 
effectively says "you need to use the full qname of something you are 
extending"

         <cdl:cdl xmlns="urn:uri:webapps" >
           <a>
             <b>100</b>
           </a>

           <cdl:system>
             <a2>
               <b>200</b>
               <a3 cdl:extends="a">
                 <b>300</b>
               </a3>
             </a2>
           </cdl:system>
         </cdl:cdl>


The reason that I believe that this must fail, that in extends="a" , the 
a template must not be found, is the same as with references: you need 
the full qname with a prefix.

-steve