update_payload: Add SOURCE operations to applier.

Add support for SOURCE_COPY and SOURCE_BSDIFF to paycheck by adding
functions to apply these operations in applier. Also remove the source
to destination partition copy in the applier when minor version is 2.

Adds constants for source and inplace minor versions to common.py.

BUG=chromium:461635
TEST=unit tests and ./test_paycheck.sh with sample payloads.
CQ-DEPEND=CL:263747

Change-Id: I72d354d0609d205aab374dbdca6f30eb4de6a819
Reviewed-on: https://chromium-review.googlesource.com/264931
Tested-by: Allie Wood <alliewood@chromium.org>
Reviewed-by: Alex Deymo <deymo@chromium.org>
Commit-Queue: Allie Wood <alliewood@chromium.org>
Trybot-Ready: Allie Wood <alliewood@chromium.org>
2 files changed