Fix App name and icon in Settings Battery details.

Set correct defaultPackageName and Label for Apps in BatteryEntry.java
so PowerUsageDetails will show the correct information.

Bug: 24187923
Fixes: 24187923
Test: Open Settings, click on Apps, select any app. Note the name and
icon on the Header. Click the Battery item. The app name and icon should
match that of the previous name, as opposed to showing the package name
and default Android icon.
Change-Id: I7b6c3b404fcd298c6670cceecd29915abd325d1f