rootfs: compare md5 checksum
rootfs: compare md5 checksum

This patch adds md5 checksum comparison to verify fedora
rootfs which is downloaded from server.

Change-Id: If54155d7c3a027064097b8e42b7efe0645c98360
Signed-off-by: Chanho Park <8ec285a53e21b773fd914e03c50e1b6431bc9aa8@samsung.com>

SamsungARTIK/build-artik