Write containerlayout element when has gridrc props but no container props

refs alejandroautalan/pygubu-designer#76

Author: alejandroautalan

pygubu/builder/uidefinition.py

@@ -312,10 +312,12 @@ def widget_to_xmlnode(self, wmeta):
 
         # Container layout properties
         container_layout_required = (
-            layout_required and wmeta.container_properties)
+            layout_required
+            and (wmeta.container_properties or wmeta.gridrc_properties)
+        )
         if container_layout_required:
             # create layout node
-            clnode = ET.Element('layout')
+            clnode = ET.Element('containerlayout')
             clnode.set('manager', wmeta.container_manager)
 
             keys = sorted(wmeta.container_properties)