This bug was only on Windows but we updated the call to 
create_temporary_file to match what is being done in other
areas of MySQL


sql/sql_partition.cc:
  the O_RDWR mode and MY_WME were used in this code before the switch
  was made to create_temp_file.  The parameters are still there
  so we just plug in the mode and WME so the underlying code will 
  create the temp file with the right mode.  This only affected 
  Windows.  [This comment was from the first changset that I was unable
  to bk fix].  This changeset adds O_BINARY | O_TRUNC | O_TEMPORARY