Don't use oflag=direct while erasing bootloader code
Don't use oflag=direct while erasing bootloader code

We are erasing 446 bytes of bootloader code before rebooting
node, but you can write only blocks with O_DIRECT, so let's
write 446 bytes without oflag=direct and do sync after dd
instead.

Change-Id: I7b5f9749b170a9b7191991dd02cb867bba0e4c43
Partial-Bug: #1573105
Closes-Bug: #1538587

stackforge/fuel-astute,stackforge/fuel-astute