The kernel configs themselves are stored as diffs of what we want vs. each
version's defconfig.
Thus, things like e.g. CONFIG_DEVKMEM drop out after it was made
non-default. The implication of this is (I hope) that as upstream adopts
security features, our delta can shrink (or more realistically, only
include the next-next gen features).
Signed-off-by: Tycho Andersen <tycho@docker.com>
