BUG#34380370 truncate table not free mutex in some case

release mutex on all return paths in truncate_t::truncate

Change-Id: I5aeee262503db191ced7773d2456bd32d7007c53

Author: GBuella

storage/innobase/fil/fil0fil.cc

@@ -7196,6 +7196,7 @@ truncate_t::truncate(
 			ib::error() << "Failed to open tablespace file "
 				<< path << ".";
 
+			mutex_exit(&fil_system->mutex);
 			ut_free(path);
 
 			return(DB_ERROR);