[IOT-1608] Support PUT,POST,DELETE method type for /oic/ping

[IOT-1608] Support PUT,POST,DELETE method type for /oic/ping

If PUT,DELETE methoed type is received for /oic/ping,
HandleKeepAliveRequest() function will respond to remote device
with error code.
bug: https://jira.iotivity.org/browse/IOT-1608

Change-Id: I47d81222cebced3505cafec8eabfe0604c94d8a3
Signed-off-by: hyuna0213.jo <hyuna0213.jo@samsung.com>
Reviewed-on: https://gerrit.iotivity.org/gerrit/14835
Tested-by: jenkins-iotivity <jenkins-iotivity@opendaylight.org>
Reviewed-by: Phil Coval <philippe.coval@osg.samsung.com>
Reviewed-by: Ziran Sun <ziran.sun@samsung.com>