dockerbuild: don't die with no args

diff --git a/scripts/docker/dockerbuild b/scripts/docker/dockerbuild
index 85704c836bbe520294984b4d2533f97191aac4a9..cade4809890212c78fc0a25fb02767b475a442d2 100755 (executable)
--- a/scripts/docker/dockerbuild
+++ b/scripts/docker/dockerbuild
@@ -6,7 +6,7 @@
 #  Example usage: ./dockerbuild build-debian9
 #
 
-set -eu
+set -e
 
 usage ()
 {
@@ -42,6 +42,8 @@ DIR="$1"
 [ -z "$DIR" ] && usage 1
 [ ! -d "$DIR" ] && echo "Directory '$DIR' does not exist" && exit 1
 
+set -u
+
 #
 #  Work out which OS to base our image on from the dir name
 #