fix compile Error on Ubuntu with Linux-3.11.0-rc6+

"open" call missed third argument when O_CREAT is given.
(according man 2 open)

Reported-and-fix-by: gokulnatha
(https://github.com/gokulnatha)

Signed-off-by: gokulnatha
Signed-off-by: zhangwei(Jovi) <jovi.zhangwei@gmail.com>