Set Default value of SimFlags.G4Commands

When we moved away from using FADS to set the G4 verbosity level we
switched to using a `SimFlag` to set a property of `G4AtlasAlg` and
`G4TransportTool` which then runs the command strings supplied via
`G4UIManager` interface. Although the configuration code attempted
to set the `SimFlag`, it was already locked and so nothing was set.
By adding the verbosity setting command as the default value of the
`SimFlag` it should always be supplied to `G4AtlasAlg` and
`G4TransportTool`.


Former-commit-id: 098c877dd4814ecc202c42e36b6fb6fa2272abd9

Simulation/G4Atlas/G4AtlasApps/python/SimFlags.py

@@ -689,7 +689,7 @@ class G4Commands(JobProperty):
     """
     statusOn = True
     allowedTypes = ['list']
-    StoredValue = []
+    StoredValue = ['/run/verbose 2'] # FIXME make configurable based on Athena message level?
 
 class UserActionConfig(JobProperty):
     """Configuration for UserActions