To libify the apply functionality we should provide a function
to check that the values in a 'struct apply_state' instance are
coherent. Let's move the code to do that into a new
check_apply_state() function.
Reviewed-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>