init_pm_metrics() fails due to adapter_agent call instead of core_proxy call

20190314T064949.899 ERROR MainThread openolt_statistics.init_pm_metrics

{ip: 192.168.96.10:50060, id: ab224c36dc57915ad504f6d3, e: 'OpenoltDevice' object has no attribute 'adapter_agent', event: pm-setup, exception: Traceback (most recent call last): File "/voltha/adapters/openolt/openolt_statistics.py", line 56, in init_pm_metrics self.pm_metrics = OltPmMetrics(self.device.adapter_agent, self.device.device_id, AttributeError: 'OpenoltDevice' object has no attribute 'adapter_agent', instance_id: 558d34115ff9_1552546023, vcore_id: None}

20190314T064950.232 DEBUG Thread-5 openolt_device.indications_thread {ip: 192.168.96.10:50060, id: ab224c36dc57915ad504f6d3, indication: olt_ind

{ oper_state: "up" }