VOL-2776 Start_omci_test is unimplemented for OLT

Change-Id: I334e5d4ca93ef5f86c46ca046499d6d95a7b36dd
diff --git a/internal/pkg/core/openolt.go b/internal/pkg/core/openolt.go
index 2e2d976..6e35a3e 100644
--- a/internal/pkg/core/openolt.go
+++ b/internal/pkg/core/openolt.go
@@ -384,3 +384,8 @@
 	}
 	return olterrors.NewErrNotFound("device-handler", log.Fields{"device-id": deviceID}, nil).Log()
 }
+
+//Start_omci_test not implemented
+func (oo *OpenOLT) Start_omci_test(device *voltha.Device, request *voltha.OmciTestRequest) (*voltha.TestResponse, error) {
+	return nil, olterrors.ErrNotImplemented
+}