Before, when a package was selected, currentPackageChanged was emitted
once from currentChanged and once from selectionChanged for the same
package.
Now it is emitted when the selection changes. It is still emitted for an
already-current package, but we need that to get the correct buttons
shown in PackageWidget when we deselect all packages except one from a
multi-selection.

Add qDebug or breakpoint in PackageWidget::packageActivated.
Run and select packages in the list view.