Kops fails to mount etcd volume for k8s 1.10 and 1.11

[hakman]

1. What kops version are you running? The command kops version, will display
this information.
latest master

2. What Kubernetes version are you running? kubectl version will print the
version if a cluster is running or provide the Kubernetes version specified as
a kops flag.
1.10 or 1.11

3. What cloud provider are you using?
AWS

4. What commands did you run? What is the simplest way to reproduce this issue?
n/a

5. What happened after the commands executed?
n/a

6. What did you expect to happen?
Cluster should start and run e2e

7. Please provide your cluster manifest. Execute
kops get --name my.example.com -o yaml to display your cluster manifest.
You may want to remove your cluster name and other sensitive information.
n/a

8. Please run the commands with most verbose logging by adding the -v 10 flag.
Paste the logs into this report, or in a gist and provide the gist link here.
https://storage.googleapis.com/kubernetes-jenkins/logs/e2e-kops-aws-k8s-1-11/1249398784325062656/artifacts/3.8.78.27/protokube.log

9. Anything else do we need to know?
This seems to be related to #8879.
The error seems to be:

W0412 18:12:27.646560    3634 volume_mounter.go:79] unable to mount master volume: "error formatting and mounting disk \"/dev/xvdu\" on \"/mnt/master-vol-00b718c718950ef02\": MountSensitive not implemented for containerized mounter"

[justinsb]

Thanks for fixing this @hakman .. I think #8939 should be sufficient!