Allow server and client to take api version as argument

* Defaults to v1beta1
* apiserver takes -storage_version which controls etcd storage version
  and the version of the client used to connect to other apiservers
* Changed signature of client.New to add version parameter
* All controller code and component code prefers the oldest (most common)
  server version

test/integration/utils.go

@@ -41,3 +41,17 @@ func withEtcdKey(f func(string)) {
 	defer newEtcdClient().Delete(prefix, true)
 	f(prefix)
 }
+
+func deleteAllEtcdKeys() {
+	client := newEtcdClient()
+	keys, err := client.Get("/", false, false)
+	if err != nil {
+		glog.Fatalf("Unable to list root etcd keys: %v", err)
+	}
+	for _, node := range keys.Node.Nodes {
+		if _, err := client.Delete(node.Key, true); err != nil {
+			glog.Fatalf("Unable delete key: %v", err)
+		}
+	}
+
+}