Remove delete request of notification sampleconsumer.

Remove delete request of notification sampleconsumer.

notification manager(resource hosting) is not service for delete request.

notification manager use to resource-encapsulation APIs.
but resource encapsulation APIs is not service for delete request to remote resource.
so, unsupported function about delete request is removed in sample application.

Change-Id: I1280b1fa647b57eadc80ff064d121593fdc88526
Signed-off-by: jyong2.kim <jyong2.kim@samsung.com>
Reviewed-on: https://gerrit.iotivity.org/gerrit/3079
Tested-by: jenkins-iotivity <jenkins-iotivity@opendaylight.org>
Reviewed-by: Hun-je Yeon <hunje.yeon@samsung.com>
Reviewed-by: Madan Lanka <lanka.madan@samsung.com>