Fix cloud-config file

This patch fixes bad generated cloud-config file due to missing double quotes.

As a result, kube-controller-manager and kubelet services fail to start.

This is a regression introduced in https://review.opendev.org/#/c/666625/.

Change-Id: I0e0a3786e084fc4d3aae3151791d79c3956d2e52
Task: 36192
Story: 2005333

magnum/drivers/common/templates/kubernetes/fragments/write-kube-os-config.sh

@@ -34,7 +34,10 @@ monitor-max-retries=3
 bs-version=v2
 EOF
 )
-echo $CLOUD_CONFIG > $KUBE_OS_CLOUD_CONFIG
+
+cat > ${KUBE_OS_CLOUD_CONFIG} <<EOF
+$CLOUD_CONFIG
+EOF
 
 # Provide optional region parameter if it's set.
 if [ -n "${REGION_NAME}" ]; then