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.

Change-Id: I29c42249b5af9363517bde971b74e8f80e8fbaa4
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>