Update tftraining.md (kubeflow#195)

Provide VERSION variable with default value for example script

content/docs/guides/components/tftraining.md

@@ -153,10 +153,11 @@ Kubeflow ships with a [ksonnet prototype](https://ksonnet.io/docs/concepts#proto
 
 You can also use this prototype to generate a component which you can then customize for your jobs.
 
-Create the component
+Create the component (update version as appropriate).
 
 ```
 CNN_JOB_NAME=mycnnjob
+VERSION=v0.2-branch
 
 ks registry add kubeflow-git github.com/kubeflow/kubeflow/tree/${VERSION}/kubeflow
 ks pkg install kubeflow-git/examples
@@ -646,4 +647,4 @@ Events:
  	   * The pod tries to mount a volume (or secret) that doesn't exist or is unavailable
  	   * The docker image doesn't exist or can't be accessed (e.g due to permission issues)
 1. If the containers start; check the logs of the containers following the instructions
-   in the previous section.
+   in the previous section.