Fix bogus use of printf in t3700 test

The hashed contents did not matter in the end result, but it passed
an uninitialized variable to printf, which caused it to emit empty
while giving an error/usage message.
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

t/t3700-add.sh

@@ -131,8 +131,8 @@ test_expect_success 'git add with filemode=0, symlinks=0 prefers stage 2 over st
 	(
 		echo "100644 $(git hash-object -w stage1) 1	file"
 		echo "100755 $(git hash-object -w stage2) 2	file"
-		echo "100644 $(printf $s | git hash-object -w -t blob --stdin) 1	symlink"
-		echo "120000 $(printf $s | git hash-object -w -t blob --stdin) 2	symlink"
+		echo "100644 $(printf 1 | git hash-object -w -t blob --stdin) 1	symlink"
+		echo "120000 $(printf 2 | git hash-object -w -t blob --stdin) 2	symlink"
 	) | git update-index --index-info &&
 	git config core.filemode 0 &&
 	git config core.symlinks 0 &&