Disable vtable deduplication

It surprises folks who are editing flatbuffers more often than not.  We
compress anything we care about space savings in, so just don't do it.

Change-Id: Ic111a9a580d3c755d7a9ccf84ba3de85dc64289b
diff --git a/aos/flatbuffer_merge.h b/aos/flatbuffer_merge.h
index 0c09b22..61dbf6b 100644
--- a/aos/flatbuffer_merge.h
+++ b/aos/flatbuffer_merge.h
@@ -29,6 +29,7 @@
                                                          const T *fb2) {
   flatbuffers::FlatBufferBuilder fbb;
   fbb.ForceDefaults(true);
+  fbb.DedupVtables(false);
   fbb.Finish(MergeFlatBuffers<T>(
       reinterpret_cast<const flatbuffers::Table *>(fb1),
       reinterpret_cast<const flatbuffers::Table *>(fb2), &fbb));
@@ -167,6 +168,7 @@
 inline FlatbufferDetachedBuffer<T> CopyFlatBuffer(const T *t) {
   flatbuffers::FlatBufferBuilder fbb;
   fbb.ForceDefaults(true);
+  fbb.DedupVtables(false);
   fbb.Finish(CopyFlatBuffer<T>(t, &fbb));
   return FlatbufferDetachedBuffer<T>(fbb.Release());
 }
@@ -175,6 +177,7 @@
 inline FlatbufferDetachedBuffer<T> RecursiveCopyFlatBuffer(const T *t) {
   flatbuffers::FlatBufferBuilder fbb;
   fbb.ForceDefaults(true);
+  fbb.DedupVtables(false);
   fbb.Finish(RecursiveCopyFlatBuffer<T>(t, &fbb));
   return FlatbufferDetachedBuffer<T>(fbb.Release());
 }