Fix incorrect usage of file module

The file module does not copy a file from src to dest.  This change
uses rsync to do so, registering a change only when rsync actually
syncs the file.

We also fix some incorrect references to what should be
{{ system_user }}.

Solution found at https://gist.github.com/maxim/7dd6e4d98d8c7d1f4961,
is there any better way of doing this?

Closes issue #302