[openssl/openssl] 6d5f63: Fix coverity 1504433: unchecked return value

[pauli]

  Branch: refs/heads/master
  Home:   https://github.openssl.org/openssl/openssl
  Commit: 6d5f636ce1ff6b57846e0e0fc82f7ed56aee2ac5
      https://github.openssl.org/openssl/openssl/commit/6d5f636ce1ff6b57846e0e0fc82f7ed56aee2ac5
  Author: Pauli <pauli at openssl.org>
  Date:   2022-05-19 (Thu, 19 May 2022)

  Changed paths:
    M ssl/ssl_rsa.c

  Log Message:
  -----------
  Fix coverity 1504433: unchecked return value

Just extending the comment so coveriety knows as well.

Reviewed-by: Tomas Mraz <tomas at openssl.org>
Reviewed-by: Matt Caswell <matt at openssl.org>
(Merged from https://github.com/openssl/openssl/pull/18326)