[recipes] Mostly remove bot_update patch_ref hack

We need to do some refactoring to remove the repository hack for
cross-repo tryjobs.

Bug: skia:6473
Change-Id: Ie96fba75f6f1752575a4c7cc5b0208a37f0bd73d
Reviewed-on: https://skia-review.googlesource.com/125724
Reviewed-by: Ben Wagner <benjaminwagner@google.com>
Commit-Queue: Eric Boren <borenet@google.com>
3 files changed