message: Use driver.(dis)connect instead of toggling simulating flag directly
diff: @@ -112,13 +112,13 @@ class Session(object):
  try:
  # TODO (artyom, 20171005): this will go away
  # once robot / driver simulation flow is fixed
  - robot._driver.simulating = True
  + robot._driver.disconnect()
  exec(self._protocol, {})
  except Exception as e:
  self.error_append(e)
  raise e
  finally:
  - robot._driver.simulating = False
  + robot._driver.connect()
  unsubscribe()
  # Accumulate containers, instruments, interactions from commands
  