Add destruction of listeners

The listeners aren't really destroyed and are only stopped. Further
changes are required so that they won't be started again once they have
been destroyed.

include/maxscale/config_runtime.h

@@ -144,3 +144,16 @@ bool runtime_create_listener(SERVICE *service, const char *name, const char *add
                              const char *auth_opt, const char *ssl_key,
                              const char *ssl_cert, const char *ssl_ca,
                              const char *ssl_version, const char *ssl_depth);
+
+/**
+ * @brief Destroy a listener
+ *
+ * This disables the listener by removing it from the polling system. It also
+ * removes any generated configurations for this listener.
+ *
+ * @param service Service where the listener exists
+ * @param name Name of the listener
+ *
+ * @return True if the listener was successfully destroyed
+ */
+bool runtime_destroy_listener(SERVICE *service, const char *name);

include/maxscale/service.h

@@ -262,13 +262,13 @@ bool serviceStop(SERVICE *service);
 bool serviceStart(SERVICE *service);
 
 /**
- * @brief Start a listener for a service
+ * @brief Start new a listener for a service
  *
  * @param service Service where the listener is linked
  * @param port Listener to start
  * @return True if listener was started
  */
-bool serviceStartListener(SERVICE *service, SERV_LISTENER *port);
+bool serviceLaunchListener(SERVICE *service, SERV_LISTENER *port);
 
 /**
  * @brief Stop a listener for a service