[openssl/openssl] 38b4ad: Fix a leak in ossl_encode_ctx_setup_for_pkey

[Matt Caswell]

  Branch: refs/heads/openssl-3.1
  Home:   https://github.com/openssl/openssl
  Commit: 38b4ad802fab79826c585eb534c65b16803d7e24
      https://github.com/openssl/openssl/commit/38b4ad802fab79826c585eb534c65b16803d7e24
  Author: Matt Caswell <matt at openssl.org>
  Date:   2023-08-23 (Wed, 23 Aug 2023)

  Changed paths:
    M crypto/encode_decode/encoder_pkey.c

  Log Message:
  -----------
  Fix a leak in ossl_encode_ctx_setup_for_pkey

Make sure we free the stack of names we allocated in an error path.

Found by the reproducible error patch in #21668

Reviewed-by: Tomas Mraz <tomas at openssl.org>
Reviewed-by: Dmitry Belyavskiy <beldmit at gmail.com>
(Merged from https://github.com/openssl/openssl/pull/21796)

(cherry picked from commit 8ef63b6ff8301a0139c00df6c40173a63fd2db01)