image_to_vm.sh: fix flag formatting

Old formatting string resulted in unordered jumbled output.

BUG=None
TEST=./image_to_vm.sh --help

Change-Id: I676c27e75a3b2f59b1171f7c60bbe19500fc6f16
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crosutils/+/3032151
Reviewed-by: Mike Frysinger <vapier@chromium.org>
Tested-by: George Engelbrecht <engeg@google.com>
Commit-Queue: George Engelbrecht <engeg@google.com>
1 file changed