Fix hard-coded 0 default for all fields in JsonToFlatbuffer

It never does anything because the public API does ForceDefaults(true),
which means the default is ignored, but it's still confusing and a
potential bug if anybody reuses this code later.

Noticed while reviewing If83978dd73a542d070eaeb242532e7ee52104999.

Change-Id: I908b4f03b9ed2b15c6c76856200ca772d259177f
Signed-off-by: Brian Silverman <brian.silverman@bluerivertech.com>
diff --git a/aos/json_to_flatbuffer.cc b/aos/json_to_flatbuffer.cc
index 6d4a2f1..e7b62d4 100644
--- a/aos/json_to_flatbuffer.cc
+++ b/aos/json_to_flatbuffer.cc
@@ -454,37 +454,37 @@
       type.FieldElementaryType(field_index);
   switch (elementary_type) {
     case flatbuffers::ET_BOOL:
-      fbb->AddElement<bool>(field_offset, int_value, 0);
+      fbb->AddElement<bool>(field_offset, int_value);
       return true;
     case flatbuffers::ET_CHAR:
-      fbb->AddElement<int8_t>(field_offset, int_value, 0);
+      fbb->AddElement<int8_t>(field_offset, int_value);
       return true;
     case flatbuffers::ET_UCHAR:
-      fbb->AddElement<uint8_t>(field_offset, int_value, 0);
+      fbb->AddElement<uint8_t>(field_offset, int_value);
       return true;
     case flatbuffers::ET_SHORT:
-      fbb->AddElement<int16_t>(field_offset, int_value, 0);
+      fbb->AddElement<int16_t>(field_offset, int_value);
       return true;
     case flatbuffers::ET_USHORT:
-      fbb->AddElement<uint16_t>(field_offset, int_value, 0);
+      fbb->AddElement<uint16_t>(field_offset, int_value);
       return true;
     case flatbuffers::ET_INT:
-      fbb->AddElement<int32_t>(field_offset, int_value, 0);
+      fbb->AddElement<int32_t>(field_offset, int_value);
       return true;
     case flatbuffers::ET_UINT:
-      fbb->AddElement<uint32_t>(field_offset, int_value, 0);
+      fbb->AddElement<uint32_t>(field_offset, int_value);
       return true;
     case flatbuffers::ET_LONG:
-      fbb->AddElement<int64_t>(field_offset, int_value, 0);
+      fbb->AddElement<int64_t>(field_offset, int_value);
       return true;
     case flatbuffers::ET_ULONG:
-      fbb->AddElement<uint64_t>(field_offset, int_value, 0);
+      fbb->AddElement<uint64_t>(field_offset, int_value);
       return true;
     case flatbuffers::ET_FLOAT:
-      fbb->AddElement<float>(field_offset, int_value, 0);
+      fbb->AddElement<float>(field_offset, int_value);
       return true;
     case flatbuffers::ET_DOUBLE:
-      fbb->AddElement<double>(field_offset, int_value, 0);
+      fbb->AddElement<double>(field_offset, int_value);
       return true;
     case flatbuffers::ET_STRING:
     case flatbuffers::ET_UTYPE:
@@ -528,10 +528,10 @@
       return false;
     }
     case flatbuffers::ET_FLOAT:
-      fbb->AddElement<float>(field_offset, double_value, 0);
+      fbb->AddElement<float>(field_offset, double_value);
       return true;
     case flatbuffers::ET_DOUBLE:
-      fbb->AddElement<double>(field_offset, double_value, 0);
+      fbb->AddElement<double>(field_offset, double_value);
       return true;
   }
   return false;