Modify NotificationManager code to change resource type

Modify NotificationManager code to change resource type

- change the capital of resource type into the small letter

Change-Id: I85d34e25c903a826f2b4a16781991ee61b75b16b
Signed-off-by: Younghyun Joo <yh_.joo@samsung.com>
Reviewed-on: https://gerrit.iotivity.org/gerrit/2835
Tested-by: jenkins-iotivity <jenkins-iotivity@opendaylight.org>
Reviewed-by: Madan Lanka <lanka.madan@samsung.com>
(cherry picked from commit 279fd705afde671ba1cff6d414a18124fbc7e2f3)
Reviewed-on: https://gerrit.iotivity.org/gerrit/2839