generate-d-i: Use "set -u"

diff --git a/scripts/debian/generate-d-i b/scripts/debian/generate-d-i
index 391e830860b51053f79d22fe8b45c44cb58c455b..d5deea458a72d9122c6cdf937dc24ed0a728be82 100755 (executable)
--- a/scripts/debian/generate-d-i
+++ b/scripts/debian/generate-d-i
@@ -3,6 +3,8 @@
 # Original written from Jeroen van Wolffelaar <jeroen@debian.org>
 
 set -e
+set -u
+
 export SCRIPTVARS=/srv/ftp-master.debian.org/dak/config/debian/vars
 . $SCRIPTVARS