bisect: cleanup whitespace errors in git-bisect.sh.

bisect: cleanup whitespace errors in git-bisect.sh.

All leading whitespace is now encoded with tabs.

After this patch, the following is true:

	RAW=$(cat git-bisect.sh | md5sum) &&
	ROUNDTRIP=$(cat git-bisect.sh | expand -i - | unexpand --first-only - | md5sum) &&
	LEADING=$(sed -n "/^  */p" < git-bisect.sh | wc -l) &&
	test $RAW = $ROUNDTRIP &&
	test $LEADING = 0 &&
	test -z "$(git diff -w HEAD~1 HEAD)"

Signed-off-by: Jon Seymour <jon.seymour@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>