tweak this so it will work out of the box with multi reg

git-svn-id: http://svn.freeswitch.org/svn/freeswitch/trunk@7892 d0543943-73ff-0310-b7d9-9358b9ac24b2

conf/directory/default.xml

@@ -2,7 +2,7 @@
   <!--the domain or ip (the right hand side of the @ in the addr-->
   <domain name="$${domain}">
     <params>
-      <param name="dial-string" value="{transfer_fallback_extension=${dialed_user}}sofia/${dialed_domain}/${dialed_user}"/>
+      <param name="dial-string" value="{transfer_fallback_extension=${dialed_user}}${sofia_contact(${dialed_domain}/${dialed_ext}@${dialed_domain})}"/>
     </params>
 
     <variables>