Use File::Path::rmtree rather than File::Path::remove_tree
Use File::Path::rmtree rather than File::Path::remove_tree

Just like File::Path::make_path, File::Path::remove_tree didn't show
up before File::Path 2.06 / perl v5.10.1, so we prefer the legacy
function here as well.

Reviewed-by: Andy Polyakov <015edf36635e030d5e009e08808a59984e629740@openssl.org>

openssl/openssl,openssl/openssl,openssl/openssl,openssl/openssl,openssl/openssl,openssl/openssl