Fix calling invalid CAfunction on Notification service.

Fix calling invalid CAfunction on Notification service.

When consumer service terminated,
consumer service will unregister Network monitoring.
but, consumer service call invalid function.

In this patch,
modify calling with valid function for unregister monitoring.

Change-Id: I89c5a7f022d144c2b98a43fd956a4155d708a4c6
Signed-off-by: KIM JungYong <jyong2.kim@samsung.com>
Reviewed-on: https://gerrit.iotivity.org/gerrit/17461
Tested-by: jenkins-iotivity <jenkins@iotivity.org>
Reviewed-by: Uze Choi <uzchoi@samsung.com>