module: zero priv_data instead of cls

to allow multiple calls of module_done to same state (as keyboard_control
is called).

otherwise dump-tree would fail

This acutally revers the commit 33bdcb4 (2020-03-13).

Author: MartinPulec

src/module.c

@@ -102,9 +102,10 @@ void module_done(struct module *module_data)
         if(!module_data)
                 return;
 
-        if (module_data->cls == MODULE_CLASS_NONE)
+        if (module_data->module_priv == NULL) {
                 return;
-        
+        }
+
         struct module_priv_state *module_priv = module_data->module_priv;
 
         assert(module_priv->magic == MODULE_MAGIC);
@@ -117,8 +118,6 @@ void module_done(struct module *module_data)
                 module_mutex_unlock(&module_priv->parent->lock);
         }
 
-        module_data->cls = MODULE_CLASS_NONE;
-
         if(simple_linked_list_size(module_priv->children) > 0) {
                 log_msg(LOG_LEVEL_WARNING, "Warning: Child database not empty! Remaining:\n");
                 dump_tree(module_data, 0);
@@ -154,6 +153,7 @@ void module_done(struct module *module_data)
         simple_linked_list_destroy(module_priv->msg_queue_children);
 
         pthread_mutex_destroy(&module_priv->lock);
+        module_data->module_priv = NULL; // to multiple deinit
         free(module_priv);
 }