tests: use double quote to quote arguments in hook for portability On windows, single quote doesn't work as quote character in hook command line, because "cmd.exe" doesn't recognize it as quoting character. And this causes failure of test. This patch uses double quote to quote arguments in hook instead of single quote for portability. Even though single quotes for "[hooks] pretxncommit" in test-clone-pull-corruption.t seems to work correctly (may MinGW sh treat specially ?) AFAIK, this patch also replaces them by double quotes for consistency.