[openssl/openssl] 8d13d9: Check for NULL when freeing the QUIC_TLS object

[Matt Caswell]

  Branch: refs/heads/master
  Home:   https://github.com/openssl/openssl
  Commit: 8d13d9e7305643c28c69c57df798b553b78c2876
      https://github.com/openssl/openssl/commit/8d13d9e7305643c28c69c57df798b553b78c2876
  Author: Matt Caswell <matt at openssl.org>
  Date:   2023-10-31 (Tue, 31 Oct 2023)

  Changed paths:
    M ssl/quic/quic_tls.c

  Log Message:
  -----------
  Check for NULL when freeing the QUIC_TLS object

Free functions are expected to be tolerant of a NULL pointer being passed.

Fixes the problem in
https://github.com/openssl/openssl/pull/21668#issuecomment-1782718328

Reviewed-by: Paul Dale <pauli at openssl.org>
Reviewed-by: Hugo Landau <hlandau at openssl.org>
Reviewed-by: Tomas Mraz <tomas at openssl.org>
(Merged from https://github.com/openssl/openssl/pull/22536)