[VOL-3916] KV-store contains ONU specific data after RPC delete_device()

Change-Id: I0623bebc847a82a5b34790c6a1ff036406899d2b
diff --git a/internal/pkg/onuadaptercore/openonu.go b/internal/pkg/onuadaptercore/openonu.go
index cb74d5a..71a9034 100644
--- a/internal/pkg/onuadaptercore/openonu.go
+++ b/internal/pkg/onuadaptercore/openonu.go
@@ -384,6 +384,11 @@
 	logger.Infow(ctx, "delete-device", log.Fields{"device-id": device.Id, "SerialNumber": device.SerialNumber})
 	if handler := oo.getDeviceHandler(ctx, device.Id, false); handler != nil {
 		var errorsList []error
+
+		handler.mutexDeletionInProgressFlag.Lock()
+		handler.deletionInProgress = true
+		handler.mutexDeletionInProgressFlag.Unlock()
+
 		if err := handler.deleteDevicePersistencyData(ctx); err != nil {
 			errorsList = append(errorsList, err)
 		}