Tighten up "arc land"

Summary:
Make sure on failure (restoreBranch()) we call `git submodule update --init --recursive` to handle all those purdy submodules. For the pushing step, wrap the push commands in the try / catch block so everything gets cleaned up nice if there's failure. BONUS - add --recursive to arc patch workflow to so nested submodules work correctly. (Crazy git users)

Fixes T3407, T2945.

Test Plan: I wasn't sure how to simulate a good "push" failure but I think this should work.

Reviewers: epriestley

Reviewed By: epriestley

CC: Korvin, aran

Maniphest Tasks: T2945, T3407

Differential Revision: https://secure.phabricator.com/D6885