s3 provider fixes

include/providers/i_provider.hpp

@@ -143,7 +143,7 @@ public:
       -> api_error = 0;
 
   [[nodiscard]] virtual auto start(api_item_added_callback api_item_added,
-                                   i_file_manager *fm) -> bool = 0;
+                                   i_file_manager *mgr) -> bool = 0;
 
   virtual void stop() = 0;