Revert "[K8S] Enable --use-service-account-credentials"

This reverts commit e9b4889.

Reason for revert: breaks cluster deployment

Change-Id: Ifefc3715acf8a87bf75c1d1aa0297db6b8333431

Author: brtkwr

magnum/drivers/common/templates/kubernetes/fragments/configure-kubernetes-master.sh

@@ -402,7 +402,7 @@ chmod 600 ${ADMIN_KUBECONFIG}
 export KUBECONFIG=${ADMIN_KUBECONFIG}
 
 # Add controller manager args
-KUBE_CONTROLLER_MANAGER_ARGS="--leader-elect=true --kubeconfig=/etc/kubernetes/admin.conf --use-service-account-credentials=true"
+KUBE_CONTROLLER_MANAGER_ARGS="--leader-elect=true --kubeconfig=/etc/kubernetes/admin.conf"
 KUBE_CONTROLLER_MANAGER_ARGS="$KUBE_CONTROLLER_MANAGER_ARGS --cluster-name=${CLUSTER_UUID}"
 KUBE_CONTROLLER_MANAGER_ARGS="${KUBE_CONTROLLER_MANAGER_ARGS} --allocate-node-cidrs=true"
 KUBE_CONTROLLER_MANAGER_ARGS="${KUBE_CONTROLLER_MANAGER_ARGS} --cluster-cidr=${PODS_NETWORK_CIDR}"