*. You need to be rooted for this.
1. Install this app: Disable Services and open it.
2. Select the 'System' tab.
3. Select the "Google Services Framework" app and uncheck (disable) the following service: SystemUpdateService
4. Come back and select the "Google Play Services" and uncheck this service: SystemUpdateService
Tested and working on Android One devices & Google Nexus.
That's it! You'll never get the update notification and neither will you be able to check it manually.
If you, by chance, feel you want the update, you can re-enable these services again to receive updates.