Fix Bug 311024 - No tooltip on empty folders

Finally it's logical to show tooltip even if folder is empty
otherwise we must click on to know why there is not tooltip and show
that it's empty

FIXED-IN: 4.10
BUG: 311024

libkdepim/statisticsproxymodel.cpp

@@ -415,7 +415,7 @@ QVariant StatisticsProxyModel::data( const QModelIndex & index, int role) const
       = sourceModel()->data( sourceIndex,
                              EntityTreeModel::CollectionRole ).value<Collection>();
 
-    if ( collection.isValid() && collection.statistics().count()>0 ) {
+    if ( collection.isValid() ) {
       const QModelIndex sourceIndex = d->sourceIndexAtFirstColumn( index );
       return d->toolTipForCollection( sourceIndex, collection );
     }