relocating some parts

* ensure REMOVE_RESERVED_HEADERS is called for internal replies
* NAT_MANAGE is relocated to ensure its called with failures

(cherry picked from commit 722af98e26)

kamailio/default.cfg

@@ -434,6 +434,7 @@ route[HANDLE_IN_DIALOG_REQUESTS]
         #!ifdef NAT_TRAVERSAL_ROLE
         if (handle_ruri_alias() != 1 && is_method("ACK") ) {
             # ACK is forwarded statelessly
+            xlog("L_INFO", "$ci|default|forward ack statelessly\n");
             route(NAT_MANAGE);
         }
         #!endif
@@ -485,6 +486,7 @@ route[HANDLE_IN_DIALOG_REQUESTS]
         #!ifdef NAT_TRAVERSAL_ROLE
         if(!isdsturiset()) {
             if (handle_ruri_alias() == 1) {
+                xlog("L_INFO", "$ci|default|message had a to-tag but can't be loose routed, routing with alias\n");
                 t_relay();
                 exit;
             };
@@ -717,6 +719,10 @@ onreply_route[INTERNAL_REPLY]
         xlog("L_INFO", "$ci|default|internal reply $T_reply_code $T_reply_reason\n");
     }
 
+    #!ifdef NAT_TRAVERSAL_ROLE
+    route(NAT_MANAGE);
+    #!endif
+
     routes("INTERNAL_REPLY_");
 
     if($rs == 100) {
@@ -729,10 +735,6 @@ onreply_route[INTERNAL_REPLY]
         }
     }
 
-    #!ifdef NAT_TRAVERSAL_ROLE
-    route(NAT_MANAGE);
-    #!endif
-
     #!ifdef ACL_ROLE
     setflag(FLAG_IS_REPLY);
     route(ACL_CHECK);
@@ -748,6 +750,8 @@ onreply_route[INTERNAL_REPLY]
         setflag(FLAG_SESSION_PROGRESS);
     }
 
+    route(REMOVE_RESERVED_HEADERS);
+
 }
 
 failure_route[INTERNAL_FAULT]
@@ -755,6 +759,10 @@ failure_route[INTERNAL_FAULT]
     # this branch handles failures (>=300) to our media servers,
     # which we can sometimes overcome by routing to another server
 
+    #!ifdef NAT_TRAVERSAL_ROLE
+    route(NAT_MANAGE);
+    #!endif
+
     routes("INTERNAL_FAULT_");
 
     # if the failure cause was due to the transaction being