libsnapshot: CreateUpdateSnapshot accepts DeltaArchiveManifest

DeltaArchiveManifest includes full update package metadata.
Now, CreateUpdateSnapshot reads the source
metadata, updates it, and write to target metadata slot as well.

Test: libsnapshot_test
Bug: 140868231

Change-Id: Ia885b336145d02111ecff1aad421cb9b1efd18c2
7 files changed