mysql_fetch_length fixed for embedded library. Now data length is stored
before the data. Pointers in row still points to the data so you have to
get *(uint*)(data_ptr - sizeof(uint)) to get data length


libmysqld/lib_sql.cc:
  bug fixed - user didn't get error description
  Protocol::net_store_data changed to store data length before the data
libmysqld/libmysqld.c:
  emb_fetch_length changed to retrive data length stored before the data