fixing number of nodes ui error
 for bindings default behaviour is inappropriate, so
 need to return non-breaking spaces if value changed is undefined

Closes-Bug: #PRD-2471

Change-Id: Ia31e4487b5129d2a37ff269f363b70e96f0f1178
Merge "fixing number of nodes ui error  for bindings default behaviour is inappropriate, so  need to return non-breaking spaces if value changed is undefined"