CBSE-473: Set right argument for delete ops

Memcached protocol requires no value for delete operation. As a result,
memcached server will treat it as invalid parameter if value is provided
for delete.

Change-Id: I5f5d80129bcb705b6a9a01616a55b06be532a36a
Merge branch 'branch_2.0.1' into branch_2.0.2

* branch_2.0.1:
  CBSE-473: Set right argument for delete ops

Change-Id: Ife73cbf4afbdc892aac94955093cbb03e638a247