As man page of open(2) suggested, we should open the same file in the same
mode, to have better performance. For some data files, we will first call
os_file_create_simple_no_error_handling_func() to open them, and then call
os_file_create_func() again. We have to make sure if DIRECT IO is specified,
these two functions should both open file with O_DIRECT.

Reviewed-by: Sunny Bains <sunny.bains@oracle.com>
RB: 8981