uninstall – Reinstall the uninstalled system application for the current user?

So, I've already posted this on reddit, but I could reach a better audience here.
I've "uninstalled" Google Play games using this guide by XDA. Now I need to reinstall it. Here's how I should be able to reinstall the application: install-existing cmd adb package
But there is a problem: my phone is on Android Lollipop, and the command does not exist there. I've manually tried to install apk back, with adb and with the normal installer of the package. The application Settings always says something like Not installed for the user "(translated from the other language).

I therefore have 2 questions:
1) In which Android version was this command introduced?
and 2) How can I recover this app?

PS: I have root access, but I would prefer a non-rooted solution.