Merge "DSUService: Deduplicate InstallUserdata() and InstallScratch()" am: c2c3a3c7d4 am: 5f2f17fc4a am: 4730b8f002

Original change: https://android-review.googlesource.com/c/platform/frameworks/base/+/1662402

Change-Id: Id1623079f1dbf0fe8bb27d67720542fc57c872a1