VOL-5209 VOL-5210 VOL-5208, race condition and crashes during onu delete fix

Change-Id: I5a5073ce6d968c2c91178fab8b4aa614dd979868
diff --git a/internal/pkg/core/device_handler.go b/internal/pkg/core/device_handler.go
index c14008e..33ba76e 100755
--- a/internal/pkg/core/device_handler.go
+++ b/internal/pkg/core/device_handler.go
@@ -4737,6 +4737,7 @@
 		v.PrepareForGarbageCollection(ctx, aDeviceID)
 		delete(dh.UniVlanConfigFsmMap, k)
 	}
+	dh.pOnuIndication = nil
 	dh.pOnuOmciDevice = nil
 	dh.pOnuTP = nil
 	dh.pOnuMetricsMgr = nil