Set shell options for reliability.

Tweak a few other small things in our shell scripts.

build/make-build-image.sh

@@ -20,6 +20,9 @@
 # Kubernetes into a tar file and put it in the right place in the output
 # directory.  It will then copy over the Dockerfile and build the kube-build
 # image.
+set -o errexit
+set -o nounset
+set -o pipefail
 
 KUBE_ROOT="$(dirname "${BASH_SOURCE}")/.."
 source "$KUBE_ROOT/build/common.sh"