fix deprecated warning QDirModel

This class is obsolete. It is provided to keep old source code working.
We strongly advise against using it in new code.

Use QFileSystemModel instead.
This class was introduced in Qt 4.4

sources/exportpropertieswidget.cpp

@@ -16,6 +16,7 @@
 	along with QElectroTech.  If not, see <http://www.gnu.org/licenses/>.
 */
 #include "exportpropertieswidget.h"
+#include <QFileSystemModel>
 
 /**
 	Constructeur
@@ -126,7 +127,7 @@ void ExportPropertiesWidget::build() {
 	dirpath_label = new QLabel(tr("Dossier cible :"), this);
 	dirpath = new QLineEdit(this);
 	QCompleter *completer = new QCompleter(this);
-	completer -> setModel(new QDirModel(completer));
+	completer -> setModel(new QFileSystemModel(completer));
 	dirpath -> setCompleter(completer);
 	button_browse = new QPushButton(tr("Parcourir"), this);
 	hboxLayout -> addWidget(dirpath_label);