t3600: make hash size independent

Instead of hard-coding a fixed length invalid object ID in the test,
compute one using the lookup tables.

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

t/t3600-rm.sh

@@ -240,12 +240,14 @@ test_expect_success 'refresh index before checking if it is up-to-date' '
 '
 
 test_expect_success 'choking "git rm" should not let it die with cruft' '
+	test_oid_init &&
 	git reset -q --hard &&
 	test_when_finished "rm -f .git/index.lock && git reset -q --hard" &&
 	i=0 &&
+	hash=$(test_oid deadbeef) &&
 	while test $i -lt 12000
 	do
-		echo "100644 1234567890123456789012345678901234567890 0	some-file-$i"
+		echo "100644 $hash 0	some-file-$i"
 		i=$(( $i + 1 ))
 	done | git update-index --index-info &&
 	git rm -n "some-file-*" | : &&