VOL-1460 Updated to use a voltha-protos repo as source for protos

Change-Id: I6e88fb3bb16f91941abaad2f0a810ebc5aa29f36
diff --git a/python/adapters/openolt/openolt_statistics.py b/python/adapters/openolt/openolt_statistics.py
index ccab90a..47cfa37 100644
--- a/python/adapters/openolt/openolt_statistics.py
+++ b/python/adapters/openolt/openolt_statistics.py
@@ -17,7 +17,7 @@
 
 from twisted.internet import reactor, defer
 from pyvoltha.adapters.extensions.kpi.olt.olt_pm_metrics import OltPmMetrics
-from pyvoltha.protos.device_pb2 import PmConfig, PmConfigs, PmGroupConfig, Port
+from voltha_protos.device_pb2 import PmConfig, PmConfigs, PmGroupConfig, Port
 
 
 class OpenOltStatisticsMgr(object):