[processing] Declare NOT_SELECTED

pblottiere · nyalldawson · commit 42199d1ad0e2 · 2018-05-21T19:06:27.000+10:00
diff --git a/python/plugins/processing/gui/wrappers.py b/python/plugins/processing/gui/wrappers.py
@@ -965,6 +965,7 @@ def selectFile(self):
 
 
 class EnumWidgetWrapper(WidgetWrapper):
+    NOT_SELECTED = '[Not selected]'
 
     def createWidget(self, useCheckBoxes=False, columns=1):
         if self.dialogType in (DIALOG_STANDARD, DIALOG_BATCH):
