Merge "pm install: clarify when --multi-package can be used" am: 1004623ba1 am: 5a07f14951 am: 98fd11dbf1

Original change: https://android-review.googlesource.com/c/platform/frameworks/base/+/2015636

Change-Id: I8a17fa4ca2fd5eb8f54358f525ee408c85dbcd06