Fix buffer overflow during message serialization.

The fridge status message grew by 8 doubles which pushed the serialized
message size above 512 bytes.

Change-Id: I554b3a9965dd5bda88fd66e630feebbb40f6e275
diff --git a/aos/common/queue_types.cc b/aos/common/queue_types.cc
index 4dd7d43..29f575c 100644
--- a/aos/common/queue_types.cc
+++ b/aos/common/queue_types.cc
@@ -18,6 +18,7 @@
   uint16_t fields_size = 0;
   for (int i = 0; i < number_fields; ++i) {
     fields_size += sizeof(fields[i]->type);
+    fields_size += sizeof(fields[i]->length);
     fields_size += sizeof(uint16_t);
     fields_size += fields[i]->name.size();
   }