setup_board: seed make.conf.user if it is empty

If people have an older chroot, this file will be empty.  Clobber it
with one that has comments so we can recover easily.

BUG=None
TEST=`sudo rm -f /etc/make.conf.user; ./setup_board --board=lumpy` created /etc/make.conf.user
TEST=`sudo truncate -s 0 /etc/make.conf.user; ./setup_board --board=lumpy` created /etc/make.conf.user
TEST=`sudo ln -sf /lakds /etc/make.conf.user; ./setup_board --board=lumpy` created /etc/make.conf.user

Change-Id: I821da8ee51c71a587671e45dd40f040bfa54bb01
Reviewed-on: https://chromium-review.googlesource.com/178880
Reviewed-by: Steev Klimaszewski <threeway@gmail.com>
Reviewed-by: Aviv Keshet <akeshet@chromium.org>
Commit-Queue: Mike Frysinger <vapier@chromium.org>
Tested-by: Mike Frysinger <vapier@chromium.org>
1 file changed