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: Junio C Hamano <gitster@pobox.com>

t/t3700-add.sh

diff --git a/t/t3700-add.sh b/t/t3700-add.sh
index b52fde8..213e924 100755
--- a/t/t3700-add.sh
+++ b/t/t3700-add.sh
@@ -131,8 +131,8 @@
 	(
 		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 &&