VOL-3588 Update OFAgent to support new version of protos

Change-Id: Ic3944779f9a600ebcd5d7a916616f473059e311e
diff --git a/internal/pkg/ofagent/refresh.go b/internal/pkg/ofagent/refresh.go
index 55865ca..8025ba7 100644
--- a/internal/pkg/ofagent/refresh.go
+++ b/internal/pkg/ofagent/refresh.go
@@ -22,7 +22,7 @@
 
 	"github.com/golang/protobuf/ptypes/empty"
 	"github.com/opencord/ofagent-go/internal/pkg/openflow"
-	"github.com/opencord/voltha-lib-go/v3/pkg/log"
+	"github.com/opencord/voltha-lib-go/v4/pkg/log"
 )
 
 func (ofa *OFAgent) synchronizeDeviceList(ctx context.Context) {