Remove using /dev/random device node

Remove using /dev/random device node

Sometimes, reading the data from "/dev/random" is very slow.
It causes that the launch request is delayed.
This patch uses rand_r() function instead of "/dev/random".

- Strace Result:
07:02:42.263885 open("/dev/random", O_RDONLY) = 52 <0.000091>
07:02:42.264160 read(52, "\335\345\32\223", 4) = 4 <15.115966>
07:02:57.380340 close(52)         = 0 <0.000092>

Change-Id: If000be930ac868fde31683a626cc99a62c3089a7
Signed-off-by: Hwankyu Jhun <h.jhun@samsung.com>