Even without this PR, the operation works well.
However, it is better to use a single slash rather than
a double slash in the path.

Even though there it kubeadm_token_ttl=0 which means that kubeadm token never expires, it is not present in `kubeadm token list` after cluster is provisioned (at least after it is running for some time) and there is issue regarding this https://github.com/kubernetes/kubeadm/issues/335, so we need to create a new temporary token during the cluster upgrade.

Remove blank lines

Update checksum for kubeadm
Use v1.9.0 kubeadm params
Include hash of ca.crt for kubeadm join
Update tag for testing upgrades
Add workaround for testing upgrades
Remove scale CI scenarios because of slow inventory parsing
in ansible 2.4.x.

Change region for tests to us-central1 to
improve ansible performance

Signed-off-by: Haiwei Liu <carllhw@gmail.com>

* Enable upgrade to kubeadm

* fix kubedns upgrade

* try upgrade route

* use init/upgrade strategy for kubeadm and ignore kubedns svc

* Use bin_dir for kubeadm

* delete more secrets

* fix waiting for terminating pods

* Manually enforce kube-proxy for kubeadm deploy

* remove proxy. update to kubeadm 1.8.0rc1

* Enable HA deploy of kubeadm

* raise delay to 60s for starting gce hosts

* kubeadm support

* move k8s master to a subtask
* disable k8s secrets when using kubeadm
* fix etcd cert serial var
* move simple auth users to master role
* make a kubeadm-specific env file for kubelet
* add non-ha CI job

* change ci boolean vars to json format

* fixup

* Update create-gce.yml

* Update create-gce.yml

* Update create-gce.yml