brillo_payload_generator: Pass the list of partitions to the generator.

The list of A/B partitions is specified in ab_partitions.txt in the
.zip file. This patch parses and passes that list to the
delta_generator.

BUG=b:24387863
TEST=brillo_payload_generator logs out passing the new flags.

Change-Id: I6c9955054efd3df4a72a0b1d33f2da9b59771f02
Reviewed-on: https://chromium-review.googlesource.com/310921
Trybot-Ready: Alex Deymo <deymo@chromium.org>
Tested-by: Alex Deymo <deymo@chromium.org>
Reviewed-by: Jason Kusuma <jkusuma@chromium.org>
Commit-Queue: Alex Deymo <deymo@chromium.org>
1 file changed