Do not save unloadable flag for submodule

This property is fundamentally per-plugin, not per-submodule.

src/modules/cache.c

@@ -251,7 +251,6 @@ size_t CacheLoad( vlc_object_t *p_this, const char *dir, module_cache_t **r )
 
             LOAD_STRING(submodule->psz_capability);
             LOAD_IMMEDIATE(submodule->i_score);
-            LOAD_IMMEDIATE(submodule->b_unloadable);
         }
 
         char *path;
@@ -539,7 +538,6 @@ static int CacheSaveSubmodule( FILE *file, const module_t *p_module )
 
     SAVE_STRING( p_module->psz_capability );
     SAVE_IMMEDIATE( p_module->i_score );
-    SAVE_IMMEDIATE( p_module->b_unloadable );
     return 0;
 
 error:

src/modules/entry.c

@@ -226,6 +226,7 @@ int vlc_plugin_set (module_t *module, module_config_t *item, int propid, ...)
             break;
 
         case VLC_MODULE_NO_UNLOAD:
+            assert (module->parent == NULL);
             module->b_unloadable = false;
             break;