Adding an example that shows how to upload a file to an arbitrary datast...

Adding an example that shows how to upload a file to an arbitrary datastore. https://github.com/vmware/pyvmomi-community-samples/issues/38
This is a personal pref here so I would be curious to what others think but Im more of a fan of ```raise SystemExit(-1)``` when doing this. Same for below when its used again.