[processing] Correctly delete processing dialogs

del only delete the python variable, not the dialog which is owned by the main window.

python/plugins/processing/gui/AlgorithmLocatorFilter.py

@@ -90,7 +90,7 @@ class AlgorithmLocatorFilter(QgsLocatorFilter):
             dlg.exec_()
             # have to manually delete the dialog - otherwise it's owned by the
             # iface mainWindow and never deleted
-            del dlg
+            dlg.deleteLater()
             if canvas.mapTool() != prevMapTool:
                 try:
                     canvas.mapTool().reset()

python/plugins/processing/gui/ProcessingToolbox.py

@@ -252,7 +252,7 @@ class ProcessingToolbox(BASE, WIDGET):
                 dlg.exec_()
                 # have to manually delete the dialog - otherwise it's owned by the
                 # iface mainWindow and never deleted
-                del dlg
+                dlg.deleteLater()
 
     def executeAlgorithm(self):
         item = self.algorithmTree.currentItem()
@@ -293,7 +293,7 @@ class ProcessingToolbox(BASE, WIDGET):
                         self.addRecentAlgorithms(True)
                 # have to manually delete the dialog - otherwise it's owned by the
                 # iface mainWindow and never deleted
-                del dlg
+                dlg.deleteLater()
             else:
                 feedback = MessageBarProgress()
                 context = dataobjects.createContext(feedback)

python/plugins/processing/gui/ScriptEditorDialog.py

@@ -280,7 +280,7 @@ class ScriptEditorDialog(BASE, WIDGET):
 
         # have to manually delete the dialog - otherwise it's owned by the
         # iface mainWindow and never deleted
-        del dlg
+        dlg.deleteLater()
 
         if canvas.mapTool() != prevMapTool:
             try:

python/plugins/processing/modeler/ModelerDialog.py

@@ -293,7 +293,7 @@ class ModelerDialog(BASE, WIDGET):
         dlg.exec_()
         # have to manually delete the dialog - otherwise it's owned by the
         # iface mainWindow and never deleted
-        del dlg
+        dlg.deleteLater()
 
     def save(self):
         self.saveModel(False)