sm: Avoid memory leaks and double double-free

* sm/certcheck.c (extract_pss_params): Avoid double free
* sm/decrypt.c (gpgsm_decrypt): goto leave instead of return
* sm/encrypt.c (encrypt_dek): release s_pkey
* sm/server.c (cmd_export): free list
(do_listkeys): free lists

--

Signed-off-by: Jakub Jelen <jjelen@redhat.com>
GnuPG-bug-id: 5393

sm/encrypt.c

@@ -473,6 +473,7 @@ encrypt_dek (const DEK dek, ksba_cert_t cert, int pk_algo,
       rc = encode_session_key (dek, &s_data);
       if (rc)
         {
+          gcry_sexp_release (s_pkey);
           log_error ("encode_session_key failed: %s\n", gpg_strerror (rc));
           return rc;
         }