If we follow your instructions verbatum,
ie
remove templates/user/ga.html
copy google_universal_analytics.html to templates/user folder
then there is an error displayed when you try to view a page
"The file doesn't exist:./templates/user/ga.html"
I believe the instructions are not clear.
Should we be 'renaming' google_universal_analytics.html to ga.html??
Also, there are now in-page tracking in the Universal GA
https://support.google.com/analytics/answer/2558867?hl=en&utm_id=ad