mroonga: tests: prevents error if sourcedir is readonly#1

grooverdan wants to merge 1 commit intoKentoku:10.0Kentoku/MariaDB:10.0from

grooverdan:k-10.0-mroonga-out-of-tree-source-imutablegrooverdan/mariadb-server:k-10.0-mroonga-out-of-tree-source-imutableCopy head branch name to clipboard