zip: Fix test failure (libarchive#2304)

Fix `test_write_format_zip_stream` failure when `HAVE_ZLIB_H` is not
defined.

If `libz` is present, `zip` archives would be compressed by default,
which requires `zip_version=20`. Otherwise, the archive is not
compressed and only requires `zip_version=10`. I'm building libarchive
on a machine not intended for developing, so basicly there's no optional
dependencies like `libz` available, guess that's why nobody else has
reported this issue.

Author: eXl5eQ

libarchive/test/test_write_format_zip_stream.c

@@ -82,6 +82,7 @@ DEFINE_TEST(test_write_format_zip_stream)
 	const char *file_name = "file";
 
 #ifndef HAVE_ZLIB_H
+	zip_version = 10;
 	zip_compression = 0;
 #endif