Update gpcp.xml

The error says I can't use package-usage-list tag as found in the OS PP. Ok, does it work here without that tag?

Author: zjbdragon

input/gpcp.xml

@@ -532,7 +532,7 @@
 <!--   1.6 Package Usage -->
 	<section title="Package Usage">
       This section contains selections and assignments that are required when the listed Functional Packages are claimed by this PP. 
-      <package-usage-list>
+
         <package-usage ref="X509">
           <usage id="usage-x509-revocation-sigalgs" title="Limitations on Signature Algorithms in FIA_X509_EXT.1.1">
             <description>
@@ -592,7 +592,7 @@
             </config>
           </usage>
         </package-usage>
-      </package-usage-list>
+
     </section>
 
 </sec:Introduction>