When Key for Ksync entry is different from Oper DB Entry, it can
so happen that multiple Oper DB entries can point to same Ksync entry

To Handle this case, introducing a list to hold duplicate Oper DB
Entries and do the following:
    - on Oper DB entry add if Ksync entry is found to be associated with
      another Open DB entry, then push the entry in duplicate entry list
    - when actively associated entry is deleted take first entry from
      duplicate entry list and trigger change on ksync entry
    - when unassociated entry gets deleted just remove the reference
      with no op