cluster: check against maximum message size, not max bson size.

Author: Christian Hergert

src/mongoc/mongoc-cluster.c

@@ -2763,7 +2763,7 @@ _mongoc_cluster_try_recv (mongoc_cluster_t *cluster,
     */
    memcpy (&msg_len, &buffer->data[buffer->off + pos], 4);
    msg_len = BSON_UINT32_FROM_LE (msg_len);
-   if ((msg_len < 16) || (msg_len > cluster->max_bson_size)) {
+   if ((msg_len < 16) || (msg_len > cluster->max_msg_size)) {
       bson_set_error (error,
                       MONGOC_ERROR_PROTOCOL,
                       MONGOC_ERROR_PROTOCOL_INVALID_REPLY,