Fix locking in ssl_cert_dup()

Properly check the return value of CRYPTO_THREAD_lock_new()

Signed-off-by: Rich Salz <rsalz@openssl.org>
Reviewed-by: Matt Caswell <matt@openssl.org>

ssl/ssl_cert.c

diff --git a/ssl/ssl_cert.c b/ssl/ssl_cert.c
index 21cfb96..8915531 100644
--- a/ssl/ssl_cert.c
+++ b/ssl/ssl_cert.c
@@ -190,7 +190,7 @@
     ret->references = 1;
     ret->key = &ret->pkeys[cert->key - cert->pkeys];
     ret->lock = CRYPTO_THREAD_lock_new();
-    if (ret == NULL) {
+    if (ret->lock == NULL) {
         SSLerr(SSL_F_SSL_CERT_DUP, ERR_R_MALLOC_FAILURE);
         OPENSSL_free(ret);
         return NULL;