Fix for Postfix-3.2 .. postfix-3.5

[Wietse Venema]

diff -ur /var/tmp/postfix-3.5.5/src/tls/tls_misc.c ./src/tls/tls_misc.c
--- /var/tmp/postfix-3.5.5/src/tls/tls_misc.c   2020-07-12 16:41:51.000000000 
-0400
+++ ./src/tls/tls_misc.c        2020-07-26 13:03:13.783128000 -0400
@@ -922,8 +922,6 @@
         */
        if (SSL_get_signature_nid(ssl, &nid) && nid != NID_undef)
            locl_sig_dgst = OBJ_nid2sn(nid);
-
-       X509_free(cert);
     }
     /* Signature algorithms for the peer end of the connection */
     if ((cert = SSL_get_peer_certificate(ssl)) != 0) {
@@ -965,6 +963,8 @@
         */
        if (SSL_get_peer_signature_nid(ssl, &nid) && nid != NID_undef)
            peer_sig_dgst = OBJ_nid2sn(nid);
+
+       X509_free(cert);
     }
     if (kex_name) {
        TLScontext->kex_name = mystrdup(kex_name);