Don't use FORMAT_BASE64 format when compressing / decompressing

When compressing, the output / input is a binary format, not a text
format like BASE64.  This is important on Windows, where a ^Z in a
text file is seen as EOF, and there could be a ^Z somewhere in a
compressed file, cutting it short as input.

Reviewed-by: Matt Caswell <matt@openssl.org>

apps/enc.c

@@ -313,6 +313,9 @@ int enc_main(int argc, char **argv)
     if (verbose)
         BIO_printf(bio_err, "bufsize=%d\n", bsize);
 
+#ifdef ZLIB
+    if (!do_zlib)
+#endif
         if (base64) {
             if (enc)
                 outformat = FORMAT_BASE64;