Fix memory leak in i2d_ASN1_bio_stream

Fix memory leak in i2d_ASN1_bio_stream

When creating a signed S/MIME message using SMIME_write_CMS()
if the reading from the bio fails, the state is therefore
still ASN1_STATE_START when BIO_flush() is called by i2d_ASN1_bio_stream().
This results in calling asn1_bio_flush_ex cleanup but will only
reset retry flags as the state is not ASN1_STATE_POST_COPY.
Therefore 48 bytes (Linux x86_64) leaked since the
ndef_prefix_free / ndef_suffix_free callbacks are not executed
and the ndef_aux structure is not freed.

By always calling free function callback in asn1_bio_free() the
memory leak is fixed.

(cherry picked from commit 3a1d2b59522163ebb83bb68e13c896188dc222c6)

Reviewed-by: Paul Dale <pauli@openssl.org>
Reviewed-by: Tomas Mraz <tomas@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/15999)