mgcp_test: Rename method as it now operates on an array of messages

This code was cleaned up, catch up and rename the method.
diff --git a/openbsc/tests/mgcp/mgcp_test.c b/openbsc/tests/mgcp/mgcp_test.c
index bbbdff5..6e0df75 100644
--- a/openbsc/tests/mgcp/mgcp_test.c
+++ b/openbsc/tests/mgcp/mgcp_test.c
@@ -80,7 +80,7 @@
 	return msg;
 }
 
-static void test_auep(void)
+static void test_messages(void)
 {
 	struct mgcp_config *cfg;
 	int i;
@@ -114,7 +114,7 @@
 {
 	osmo_init_logging(&log_info);
 
-	test_auep();
+	test_messages();
 
 	printf("Done\n");
 	return EXIT_SUCCESS;