Remove INCREMENTAL_VERSION and add version to INCREMENTAL feature.

This is addressing the API feedback.

Bug: 181015045
Fixes: 181015045
Test: atest PackageManagerShellCommandTest PackageManagerShellCommandIncrementalTest IncrementalServiceTest PackageManagerServiceTest ChecksumsTest
Change-Id: I3ea745a4f0f0a0d9ae90f0625dfce61a8649a76d
3 files changed