Comment 0 for bug 1640671

Testing MAAS on OpenStack environment, but got Power error from the first instance.
Found the following error in /var/log/maas/regiond.log

2016-11-10 12:41:38 [-] Failed to update power state of machine.
        Traceback (most recent call last):
          File "/usr/lib/python3/dist-packages/twisted/internet/base.py", line 1203, in mainLoop
            self.runUntilCurrent()
          File "/usr/lib/python3/dist-packages/twisted/internet/base.py", line 798, in runUntilCurrent
            f(*a, **kw)
          File "/usr/lib/python3/dist-packages/twisted/internet/defer.py", line 434, in errback
            self._startRunCallbacks(fail)
          File "/usr/lib/python3/dist-packages/twisted/internet/defer.py", line 501, in _startRunCallbacks
            self._runCallbacks()
        --- <exception caught here> ---
          File "/usr/lib/python3/dist-packages/twisted/internet/defer.py", line 588, in _runCallbacks
            current.result = callback(current.result, *args, **kw)
          File "/usr/lib/python3/dist-packages/maasserver/websockets/handlers/machine.py", line 799, in eb_unknown
            failure.trap(UnknownPowerType, NotImplementedError)
          File "/usr/lib/python3/dist-packages/twisted/python/failure.py", line 342, in trap
            self.raiseException()
          File "/usr/lib/python3/dist-packages/twisted/python/failure.py", line 368, in raiseException
            raise self.value.with_traceback(self.tb)
          File "/usr/lib/python3/dist-packages/twisted/python/threadpool.py", line 246, in inContext
            result = inContext.theWork()
          File "/usr/lib/python3/dist-packages/twisted/python/threadpool.py", line 262, in <lambda>
            inContext.theWork = lambda: context.call(ctx, func, *args, **kw)
          File "/usr/lib/python3/dist-packages/twisted/python/context.py", line 118, in callWithContext
            return self.currentContext().callWithContext(ctx, func, *args, **kw)
          File "/usr/lib/python3/dist-packages/twisted/python/context.py", line 81, in callWithContext
            return func(*args,**kw)
          File "/usr/lib/python3/dist-packages/provisioningserver/utils/twisted.py", line 937, in callInContext
            return func(*args, **kwargs)
          File "/usr/lib/python3/dist-packages/maasserver/models/node.py", line 2897, in _get_bmc_client_connection_info
            self.hostname))
        maasserver.exceptions.PowerProblem: No rack controllers can access the BMC of node: test