PerfMonComps: Do not overwrite topSequence in the configuration

This should fix the obscure issue @emoyse reported about not being able to set a tool's output-level through topSequence in the post-exec when threads>1.

cc: @wlampl @elmsheus

Control/PerformanceMonitoring/PerfMonComps/python/PerfMonFlags.py

@@ -135,22 +135,22 @@ class doMonitoringMT(JobProperty):
             svcMgr += PerfMonMTSvc("PerfMonMTSvc")
         # Setup PerfMonAlg
         from AthenaCommon.AlgSequence import AthSequencer
-        topSequence = AthSequencer("AthAlgSeq")
-        if not hasattr(topSequence, "PerfMonMTAlg"):
+        algSeq = AthSequencer("AthAlgSeq")
+        if not hasattr(algSeq, "PerfMonMTAlg"):
             from PerfMonComps.PerfMonCompsConf import PerfMonMTAlg
-            topSequence += PerfMonMTAlg("PerfMonMTAlg")
+            algSeq += PerfMonMTAlg("PerfMonMTAlg")
         return
 
     def _undo_action(self):
         # Uninstall the service and the algorithm
         from AthenaCommon.AppMgr import ServiceMgr as svcMgr
         from AthenaCommon.AlgSequence import AthSequencer
-        topSequence = AthSequencer("AthAlgSeq")
+        algSeq = AthSequencer("AthAlgSeq")
 
         if hasattr(svcMgr, 'PerfMonMTSvc'):
             del svcMgr.PerfMonMTSvc
-        if hasattr(topSequence, 'PerfMonMTAlg'):
-            del topSequence.PerfMonMTAlg
+        if hasattr(algSeq, 'PerfMonMTAlg'):
+            del algSeq.PerfMonMTAlg
         return
 #
 class doFastMonMT(JobProperty):