[Broker] Fix auth plugin cleanup function not being called.

Closes #900.

Thanks to Julian Zhao.

Signed-off-by: Roger A. Light <roger@atchoo.org>

ChangeLog.txt

@@ -1,3 +1,11 @@
+1.5.1 - 2018xxxx
+================
+
+Broker:
+- Fix plugin cleanup function not being called on exit of the broker.
+  Closes #900.
+
+
 1.5 - 20180502
 ==============
 

src/security.c

@@ -282,6 +282,20 @@ static void security__module_cleanup_single(struct mosquitto__security_options *
 	int i;
 
 	for(i=0; i<opts->auth_plugin_config_count; i++){
+		/* Run plugin cleanup function */
+		if(opts->auth_plugin_configs[i].plugin.version == 3){
+			opts->auth_plugin_configs[i].plugin.plugin_cleanup_v3(
+					opts->auth_plugin_configs[i].plugin.user_data,
+					opts->auth_plugin_configs[i].options,
+					opts->auth_plugin_configs[i].option_count);
+
+		}else if(opts->auth_plugin_configs[i].plugin.version == 2){
+			opts->auth_plugin_configs[i].plugin.plugin_cleanup_v2(
+					opts->auth_plugin_configs[i].plugin.user_data,
+					(struct mosquitto_auth_opt *)opts->auth_plugin_configs[i].options,
+					opts->auth_plugin_configs[i].option_count);
+		}
+
 		if(opts->auth_plugin_configs[i].plugin.lib){
 			LIB_CLOSE(opts->auth_plugin_configs[i].plugin.lib);
 		}