Add glide.yaml and vendor deps

vendor/k8s.io/kubernetes/cluster/images/etcd/rollback/README.md

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+# Rollback workflow
+
+Build it in this directory.
+Make sure you have etcd dependency ready. Last time we use etcd v3.0.7.
+```
+$ go build .
+```
+
+
+Run it:
+```
+$ ./rollback2 --data-dir $ETCD_DATA_DIR --ttl 1h
+```
+
+This will rollback KV pairs from v3 into v2.
+If a key was attached to a lease before, it will be created with given TTL (default to 1h).
+
+On success, it will print at the end:
+```
+Finished successfully
+```
+
+Repeat this on all etcd members.
+
+You can do simple check on keys (if any exists):
+```
+etcdctl ls /
+```
+
+Important Note
+------
+
+This tool isn't recommended to use if any problem comes up in etcd3 backend.
+Please report bugs and we will fix it soon.
+
+If it's still preferred to run this tool, please backup all your data beforehand.
+This tool will also back up datadir to same path with ".rollback.backup" suffix.
+
+Caveats:
+- The tool doesn't preserve versions of keys.
+- If any v2 data exists before rollback, they will be wiped out.
+- v3 data only exists in the backup after successful rollback.
+
+
+[![Analytics](https://kubernetes-site.appspot.com/UA-36037335-10/GitHub/cluster/images/etcd/rollback/README.md?pixel)]()