beta: phase out shell autoupdater

We used to have a shell to automatically update the MediaWiki code
bases.  I have rewrote it in python (9a39f008), it got deployed and the
Jenkins job has been updated.

Change-Id: I7dd62ce48c11cf16b9af7b31a55df6e702d80623
Merge "beta: phase out shell autoupdater" into production