Made AthenaPoolSnvSvc.ReadAthenaPool work "standalone".

Previously the module would only work correctly if somebody upstream
already imported the AthenaCommon.AthenaCommonFlags module. With this
update it is now possible to import this module from vanilla Python
as well.

Database/AthenaPOOL/AthenaPoolCnvSvc/python/ReadAthenaPool.py

-# Copyright (C) 2002-2017 CERN for the benefit of the ATLAS collaboration
+# Copyright (C) 2002-2020 CERN for the benefit of the ATLAS collaboration
 
 ## @file ReadAthena.py
 ## @brief AthenaPool python module for reading event objects.
@@ -59,26 +59,26 @@ def _configureReadAthenaPool():
     # Add in EventSelector
     svcMgr += CfgMgr.EventSelectorAthenaPool ("EventSelector")
     #default InputCollections to FilesInput value of AthenaCommonFlags
-    from AthenaCommon.JobProperties import jobproperties as jps
+    from AthenaCommon.AthenaCommonFlags import jobproperties as jps
     svcMgr.EventSelector.InputCollections = jps.AthenaCommonFlags.FilesInput()
-    
+
     _n = svcMgr.EventSelector.getFullJobOptName()
     theApp.EvtSel = _n
     del _n
 
     # For Analysis release use lower heartbeat
-    import os 
-    if "AthAnalysisBase" in os.environ.get('CMTEXTRATAGS',""): 
-        # From Will Buttinger to suppress the event loop heartbeat as it is somewhat I/O hungry for 
-        # no real gain in analysis scenarii 
-        if not hasattr(svcMgr, theApp.EventLoop): 
-            svcMgr += getattr(CfgMgr, theApp.EventLoop)() 
-        evtloop = getattr(svcMgr, theApp.EventLoop) 
-        try: 
-            evtloop.EventPrintoutInterval = 10000 
+    import os
+    if "AthAnalysisBase" in os.environ.get('CMTEXTRATAGS',""):
+        # From Will Buttinger to suppress the event loop heartbeat as it is somewhat I/O hungry for
+        # no real gain in analysis scenarii
+        if not hasattr(svcMgr, theApp.EventLoop):
+            svcMgr += getattr(CfgMgr, theApp.EventLoop)()
+        evtloop = getattr(svcMgr, theApp.EventLoop)
+        try:
+            evtloop.EventPrintoutInterval = 10000
         except Exception:
-            msg.info('failed suppressing event loop heartbeat. performances might be sub-par... sorry.') 
-            pass 
+            msg.info('failed suppressing event loop heartbeat. performances might be sub-par... sorry.')
+            pass
 
     # Add in AthenaPoolAddressProviderSvc
     if not hasattr (svcMgr, 'AthenaPoolAddressProviderSvc'):