From d1cb1de5af4a9e17da7932aaf491cb6fa62f742e Mon Sep 17 00:00:00 2001
From: Wojciech Tyczynski <wojtekt@google.com>
Date: Thu, 17 Dec 2015 13:54:56 +0100
Subject: [PATCH] Fix unbound variable issue

---
 cluster/common.sh | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/cluster/common.sh b/cluster/common.sh
index 5dfb4f9e24..39a62965e0 100755
--- a/cluster/common.sh
+++ b/cluster/common.sh
@@ -337,7 +337,7 @@ function find-release-tars() {
 
   # This tarball is only used by Ubuntu Trusty.
   KUBE_MANIFESTS_TAR=
-  if [[ "${KUBE_OS_DISTRIBUTION}" == "trusty" ]]; then
+  if [[ "${KUBE_OS_DISTRIBUTION:-}" == "trusty" ]]; then
     KUBE_MANIFESTS_TAR="${KUBE_ROOT}/server/kubernetes-manifests.tar.gz"
     if [[ ! -f "${KUBE_MANIFESTS_TAR}" ]]; then
       KUBE_MANIFESTS_TAR="${KUBE_ROOT}/_output/release-tars/kubernetes-manifests.tar.gz"