VOL-1478 Updated statistics to pass in serial_number stats libraries, so it doesn't have to query the core

Change-Id: If355de3c7733bd22520a274bbbffeb8aea4d37e7
diff --git a/python/adapters/openolt/openolt_statistics.py b/python/adapters/openolt/openolt_statistics.py
index e9ffecc..38e9615 100644
--- a/python/adapters/openolt/openolt_statistics.py
+++ b/python/adapters/openolt/openolt_statistics.py
@@ -54,7 +54,7 @@
                     'pon-ports': self.southbound_ports.values()
                 }
                 self.pm_metrics = OltPmMetrics(self.device.core_proxy, self.device.device_id,
-                                               self.device.logical_device_id,
+                                               self.device.logical_device_id, self.device.serial_number,
                                                grouped=True, freq_override=False,
                                                **kwargs)
                 """