Couchstore expects native endianness

The items are written to disk on the Erlang side and then processed
on the C side.

Change-Id: Ide1907b5421af377ead9599b4ac87feeb500e4f6
Reviewed-on: http://review.couchbase.org/40137
Reviewed-by: Volker Mische <volker.mische@gmail.com>
Tested-by: Volker Mische <volker.mische@gmail.com>