example aligned to new exec module

examples/exec.cfg

@@ -26,7 +26,7 @@ route{
 	exec_msg("printenv SRCIP > /tmp/exectest.txt; cat >> /tmp/exectest.txt");
 	# and then rewrite URI using external utility
 	# note that the last echo command trashes input parameter
-	if (exec_uri("echo sip:[email protected];echo sip:[email protected];echo>/dev/null")) {
+	if (exec_dst("echo sip:[email protected];echo sip:[email protected];echo>/dev/null")) {
 		sl_send_reply("300", "Redirect");
 	} else {
 		sl_reply_error();