OC_Updater::ShowUpdatingHint no longer exists in master

Removed OC_Updater::ShowUpdatingHint since for master we show update notification on all pages

To reproduce pull recent master and browse to the admin page:

![admin](https://f.cloud.github.com/assets/991300/744366/11a3cb2a-e3fb-11e2-9184-a7162d75c691.png)

@schiesbn @DeepDiver1975