RT1909: Omit version for v1 certificates

When calling X509_set_version to set v1 certificate, that
should mean that the version number field is omitted.
Reviewed-by: NDr. Stephen Henson <steve@openssl.org>

crypto/x509/x509_set.c

@@ -66,6 +66,12 @@
 int X509_set_version(X509 *x, long version)
 	{
 	if (x == NULL) return(0);
+	if (version == 0)
+		{
+		M_ASN1_INTEGER_free(x->cert_info->version);
+		x->cert_info->version = NULL;
+		return(1);
+		}
 	if (x->cert_info->version == NULL)
 		{
 		if ((x->cert_info->version=M_ASN1_INTEGER_new()) == NULL)