Don't write out a bad OID

If we don't have OID data for an object then we should fail if we
are asked to encode the ASN.1 for that OID.

Fixes #5723
Reviewed-by: NRich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/5725)

crypto/asn1/tasn_enc.c

@@ -528,6 +528,8 @@ static int asn1_ex_i2c(ASN1_VALUE **pval, unsigned char *cout, int *putype,
         otmp = (ASN1_OBJECT *)*pval;
         cont = otmp->data;
         len = otmp->length;
+        if (cont == NULL || len == 0)
+            return -1;
         break;
 
     case V_ASN1_NULL: