[Bug-tar] Test #24 (extrac07.at)

[jeff]

Leaving the write bit unset after the test makes for ugly test output and the 
inability to rm -rf
the source tree without chmod'ing it first.

 24: extracting symlinks to a read-only dir       ok
rm: cannot remove `/home/j/tar-1.17/tests/testsuite.dir/24/gnu/out/dir/foo': 
Permission denied
rm: cannot remove `/home/j/tar-1.17/tests/testsuite.dir/24/gnu/dir/foo': 
Permission denied
rm: cannot remove `/home/j/tar-1.17/tests/testsuite.dir/24/oldgnu/out/dir/foo': 
Permission denied
rm: cannot remove `/home/j/tar-1.17/tests/testsuite.dir/24/oldgnu/dir/foo': 
Permission denied
rm: cannot remove `/home/j/tar-1.17/tests/testsuite.dir/24/ustar/out/dir/foo': 
Permission denied
rm: cannot remove `/home/j/tar-1.17/tests/testsuite.dir/24/ustar/dir/foo': 
Permission denied
rm: cannot remove `/home/j/tar-1.17/tests/testsuite.dir/24/v7/out/dir/foo': 
Permission denied
rm: cannot remove `/home/j/tar-1.17/tests/testsuite.dir/24/v7/dir/foo': 
Permission denied
rm: cannot remove `/home/j/tar-1.17/tests/testsuite.dir/24/posix/out/dir/foo': 
Permission denied
rm: cannot remove `/home/j/tar-1.17/tests/testsuite.dir/24/posix/dir/foo': 
Permission denied