Docs: Updating/correcting PXF subnabv

gpdb-doc/book/master_middleman/source/subnavs/pxf-subnav.erb

@@ -24,7 +24,7 @@
                 <a href="/docs/5110/pxf/cfginitstart_pxf.html" format="markdown">Configuring, Initializing, and Managing PXF</a>
               </li>
               <li>
-                <a href="/docs/600/pxf/pxf_kerbhdfs.html" format="markdown">Configuring PXF for Secure HDFS</a>
+                <a href="/docs/5110/pxf/pxf_kerbhdfs.html" format="markdown">Configuring PXF for Secure HDFS</a>
               </li>
             </ul>
           </li>
@@ -57,6 +57,9 @@
         <li>
            <a href="/docs/5110/pxf/hbase_pxf.html" format="markdown">Accessing HBase Table Data with PXF</a>
         </li>
+        <li>
+           <a href="/docs/5110/pxf/jdbc_pxf.html" format="markdown">Accessing an External SQL Database with PXF (JDBC)</a>
+        </li>
         <li>
            <a href="/docs/5110/pxf/troubleshooting_pxf.html" format="markdown">Troubleshooting PXF</a>
         </li>