Changed the /oic/ping resource registration condition.

Changed the /oic/ping resource registration condition.

In order to register /oic/ping resource in case host is not client,
I modified the keepalive init/terminate logic.

Signed-off-by: hyuna0213.jo <hyuna0213.jo@samsung.com>
Reviewed-on: https://gerrit.iotivity.org/gerrit/5571
Reviewed-by: Phil Coval <philippe.coval@osg.samsung.com>
Tested-by: jenkins-iotivity <jenkins-iotivity@opendaylight.org>
Reviewed-by: jihwan seo <jihwan.seo@samsung.com>
Reviewed-by: Jee Hyeok Kim <jihyeok13.kim@samsung.com>
(cherry picked from commit 47c277017baf1e4bed04f2b84132b2cc87bdfcfa)

Change-Id: I4a47b4576408a09a1e97a3c8eeb04ba089a3c760
Signed-off-by: hyuna0213.jo <hyuna0213.jo@samsung.com>
Reviewed-on: https://gerrit.iotivity.org/gerrit/5739
Tested-by: jenkins-iotivity <jenkins-iotivity@opendaylight.org>
Reviewed-by: Jaehong Jo <jaehong.jo@samsung.com>
Reviewed-by: Jon A. Cruz <jon@joncruz.org>