[VOL-2673]:added check to verify deletion of onu devices on deleting same.

Change-Id: If01e3ccca6bfd605cee5f5a46a3cddc2b4e6a483
diff --git a/rw_core/core/common_test.go b/rw_core/core/common_test.go
index 1128cde..346198d 100644
--- a/rw_core/core/common_test.go
+++ b/rw_core/core/common_test.go
@@ -159,7 +159,7 @@
 	go func() {
 		for {
 			device, _ := nbi.GetDevice(getContext(), &voltha.ID{Id: deviceID})
-			if device != nil && verificationFunction(device) {
+			if verificationFunction(device) {
 				ch <- 1
 				break
 			}