Fix acl_file being ignore for default listener if with per_listener_settings

Close #1073. Thanks to Jef Driesen.

Bug: https://github.com/eclipse/mosquitto/issues/1073

ChangeLog.txt

@@ -1,6 +1,11 @@
 1.5.5 - 201812xx
 ================
 
+Security:
+- If `per_listener_settings` is set to true, then the `acl_file` setting was
+  ignored for the "default listener" only. This has been fixed. This does not
+  affect any listeners defined with the `listener` option. Closes #1073.
+
 Broker:
 - Add `socket_domain` option to allow listeners to disable IPv6 support.
   This is required to work around a problem in libwebsockets that means

src/conf.c

@@ -497,6 +497,7 @@ int config__parse_args(struct mosquitto_db *db, struct mosquitto__config *config
 		config->listeners[config->listener_count-1].use_identity_as_username = config->default_listener.use_identity_as_username;
 		config->listeners[config->listener_count-1].use_subject_as_username = config->default_listener.use_subject_as_username;
 #endif
+		config->listeners[config->listener_count-1].security_options.acl_file = config->default_listener.security_options.acl_file;
 		config->listeners[config->listener_count-1].security_options.password_file = config->default_listener.security_options.password_file;
 		config->listeners[config->listener_count-1].security_options.psk_file = config->default_listener.security_options.psk_file;
 		config->listeners[config->listener_count-1].security_options.auth_plugin_configs = config->default_listener.security_options.auth_plugin_configs;