Import Upstream version 4.12.4

ipatests/test_xmlrpc/tracker/base.py

@@ -155,9 +155,7 @@ class ModificationTracker(BaseTracker):
         result = command()
         self.attrs.update(updates)
         self.attrs.update(expected_updates)
-        for key, value in self.attrs.items():
-            if value is None:
-                del self.attrs[key]
+        self.attrs = {k: v for k, v in self.attrs.items() if v is not None}
 
         self.check_update(
             result,
@@ -302,6 +300,11 @@ class EnableTracker(BaseTracker):
         (enabled/disabled) after the test as it was before it.
         """
         def cleanup():
+            if isinstance(self, CreationTracker):
+                # special case: if it already got deleted there is
+                # nothing to enable or disable
+                return
+
             if self.original_enabled != self.enabled:
                 if self.original_enabled:
                     command = self.make_enable_command()