Add utility to pad a given hash for PKCS1.5 signatures

BUG=n0ne
TEST=manual

Review URL: http://codereview.chromium.org/6334133

Change-Id: I2dced174f41e5dea2e165f18ecbd22a7f40acab3
diff --git a/scripts/sign_data.sh b/scripts/sign_data.sh
index bd9e1be..05de5a6 100755
--- a/scripts/sign_data.sh
+++ b/scripts/sign_data.sh
@@ -10,4 +10,4 @@
   exit -1
 fi
 
-./signature_digest $1 $3 | openssl rsautl -sign -pkcs -inkey $2 
+./signature_digest_utility $1 $3 | openssl rsautl -sign -pkcs -inkey $2