bisect: switch to using the_hash_algo

Instead of using GIT_SHA1_HEXSZ, use the_hash_algo so that the code is
hash size independent.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

bisect.c

@@ -707,7 +707,7 @@ static int bisect_checkout(const struct object_id *bisect_rev, int no_checkout)
 {
 	char bisect_rev_hex[GIT_MAX_HEXSZ + 1];
 
-	memcpy(bisect_rev_hex, oid_to_hex(bisect_rev), GIT_SHA1_HEXSZ + 1);
+	memcpy(bisect_rev_hex, oid_to_hex(bisect_rev), the_hash_algo->hexsz + 1);
 	update_ref(NULL, "BISECT_EXPECTED_REV", bisect_rev, NULL, 0, UPDATE_REFS_DIE_ON_ERR);
 
 	argv_checkout[2] = bisect_rev_hex;