Fix a crash when transferring an app.

This crash occurs because the background loader is loading
the storage for an app which is currently being moved off of
the device. In the native code which is calculating the storage,
it throws an InstallerException which is caught and rethrown as an
IllegalStateException.

We handle this in the view by reporting that we could not calculate
the size of the app.

Change-Id: I109b1be60ae60f8ef31b08cb4392b576261fa806
Fixes: 35922033
Test: Robotest