update_payload: Regenerate proto file with new operation codes.

Regenerate update_metadata_pb2.py to include SOURCE_COPY and
SOURCE_BSDIFF, the new a to b operations for delta minor version 2.

TEST=unit tests and `cbuildbot --remote link-release --hwtest`

Change-Id: I3631c7af97f57d48f86a34c37f97ec8c3cef088d
Reviewed-on: https://chromium-review.googlesource.com/250954
Reviewed-by: Alex Deymo <deymo@chromium.org>
Commit-Queue: Allie Wood <alliewood@chromium.org>
Tested-by: Allie Wood <alliewood@chromium.org>
Reviewed-by: Don Garrett <dgarrett@chromium.org>
2 files changed