Use get_data on SelectionData to retrieve raw data

In Gtk 3.0 there is no more data property.

Closes #11514

tryton/tryton/gui/window/view_form/view/form_gtk/image.py

@@ -84,7 +84,7 @@ class Image(BinaryMixin, Widget):
                 self.field.set_client(self.record, url_open(uri).read())
             self.update_img()
         elif info == 1:
-            uri = selection.data.split('\r\n')[0]
+            uri = selection.get_data().split('\r\n')[0]
             if uri:
                 self.field.set_client(self.record, url_open(uri).read())
             self.update_img()

tryton/tryton/gui/window/win_csv.py

@@ -278,10 +278,7 @@ class WinCSV(NoModal):
     def drag_data_received(self, treeview, context, x, y, selection,
             info, etime):
         treeview.stop_emission_by_name('drag-data-received')
-        try:
-            selection_data = selection.data
-        except AttributeError:
-            selection_data = selection.get_data()
+        selection_data = selection.get_data()
         if not selection_data:
             return
         selection_data = selection_data.decode('utf-8')