[netinstall] Update subgroup-checkedness based on children

- An unselected group with (some) selected subgroups was not
  displayed as (semi)checked -- it was unchecked, because
  its checked-ness was not updated based on the children.

src/modules/netinstall/PackageModel.cpp

@@ -249,6 +249,10 @@ PackageModel::setupModelData( const QVariantList& groupList, PackageTreeItem* pa
             if ( !subgroups.isEmpty() )
             {
                 setupModelData( subgroups, item );
+                // The children might be checked while the parent isn't (yet).
+                // Children are added to their parent (below) without affecting
+                // the checked-state -- do it manually.
+                item->updateSelected();
             }
         }
         if ( item->isHidden() )

src/modules/netinstall/PackageTreeItem.cpp

@@ -194,34 +194,41 @@ PackageTreeItem::setSelected( Qt::CheckState isSelected )
         return;
     }
 
+    currentItem->updateSelected();
+}
+
+void
+PackageTreeItem::updateSelected()
+{
     // Figure out checked-state based on the children
     int childrenSelected = 0;
     int childrenPartiallySelected = 0;
-    for ( int i = 0; i < currentItem->childCount(); i++ )
+    for ( int i = 0; i < childCount(); i++ )
     {
-        if ( currentItem->child( i )->isSelected() == Qt::Checked )
+        if ( child( i )->isSelected() == Qt::Checked )
         {
             childrenSelected++;
         }
-        if ( currentItem->child( i )->isSelected() == Qt::PartiallyChecked )
+        if ( child( i )->isSelected() == Qt::PartiallyChecked )
         {
             childrenPartiallySelected++;
         }
     }
     if ( !childrenSelected && !childrenPartiallySelected )
     {
-        currentItem->setSelected( Qt::Unchecked );
+        setSelected( Qt::Unchecked );
     }
-    else if ( childrenSelected == currentItem->childCount() )
+    else if ( childrenSelected == childCount() )
     {
-        currentItem->setSelected( Qt::Checked );
+        setSelected( Qt::Checked );
     }
     else
     {
-        currentItem->setSelected( Qt::PartiallyChecked );
+        setSelected( Qt::PartiallyChecked );
     }
 }
 
+
 void
 PackageTreeItem::setChildrenSelected( Qt::CheckState isSelected )
 {

src/modules/netinstall/PackageTreeItem.h

@@ -120,6 +120,13 @@ public:
     void setSelected( Qt::CheckState isSelected );
     void setChildrenSelected( Qt::CheckState isSelected );
 
+    /** @brief Update selectedness based on the children's states
+     *
+     * This only makes sense for groups, which might have packages
+     * or subgroups; it checks only direct children.
+     */
+    void updateSelected();
+
     // QStandardItem methods
     int type() const override;