don't segfault when -nonat is used and nat_map reinit is called

git-svn-id: http://svn.freeswitch.org/svn/freeswitch/trunk@16253 d0543943-73ff-0310-b7d9-9358b9ac24b2

src/mod/applications/mod_commands/mod_commands.c

@@ -112,6 +112,11 @@ SWITCH_STANDARD_API(nat_map_function)
 	if (!cmd) {
 		goto error;
 	}
+	
+	if (!switch_nat_is_initialized()) {
+		switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_ERROR, "nat_map API called while NAT not initialized\n");
+		goto error;
+	}
 
 	mydata = strdup(cmd);
 	switch_assert(mydata);