fix typo in comment

include/libtorrent/torrent.hpp

@@ -1030,7 +1030,7 @@ namespace libtorrent
 
 		// renames the file with the given index to the new name
 		// the name may include a directory path
-		// returns false on failure
+		// posts alert to indicate success or failure
 		void rename_file(int index, std::string const& name);
 
 		// unless this returns true, new connections must wait