Merge branch 'oldconf.AthenaConfiguration-20210326' into 'master'

AthenaConfiguration+AthenaCommon: Fix for reading old configuration.

See merge request atlas/athena!42050

Control/AthenaCommon/share/GenerateBootstrapTest.ref

 Willing to acquire file bootstrap.pkl from
 /afs/cern.ch/user/s/ssnyder/atlas-work3/build-x86_64-centos7-gcc8-dbg/x86_64-centos7-gcc8-dbg/share/bootstrap.pkl
 copy bootstrap.pkl
-... Read 2 items from python pickle file:  bootstrap.pkl
-... Read 2 items from python pickle file:  bootstrap_test.pkl
+... Read defaultdict from bootstrap.pkl
+... Read 27 items from python pickle file:  bootstrap.pkl
+... Read defaultdict from bootstrap_test.pkl
+... Read 27 items from python pickle file:  bootstrap_test.pkl
 Step 1: reference file #components: 27
 Step 2: file to check  #components: 27
 Willing to acquire file bootstrap_threaded.pkl from
 /afs/cern.ch/user/s/ssnyder/atlas-work3/build-x86_64-centos7-gcc8-dbg/x86_64-centos7-gcc8-dbg/share/bootstrap_threaded.pkl
 copy bootstrap_threaded.pkl
-... Read 2 items from python pickle file:  bootstrap_threaded.pkl
-... Read 2 items from python pickle file:  bootstrap_threaded_test.pkl
+... Read defaultdict from bootstrap_threaded.pkl
+... Read 34 items from python pickle file:  bootstrap_threaded.pkl
+... Read defaultdict from bootstrap_threaded_test.pkl
+... Read 34 items from python pickle file:  bootstrap_threaded_test.pkl
 Step 1: reference file #components: 34
 Step 2: file to check  #components: 34

Control/AthenaConfiguration/python/iconfTool/models/loaders.py

-# Copyright (C) 2002-2020 CERN for the benefit of the ATLAS collaboration
+# Copyright (C) 2002-2021 CERN for the benefit of the ATLAS collaboration
 
 import pickle
 import logging
@@ -85,6 +85,8 @@ def loadConfigFile(fname, args) -> Dict:
                 cfg, (collections.defaultdict, dict)
             ):  # old configuration
                 conf.update(cfg)
+                conf.update(pickle.load(input_file)) # special services
+                # FIXME: there's a third pickle object with python components
             elif isinstance(cfg, (collections.Sequence)):
                 for c in cfg:
                     conf.update(c)