Fix for multiple discovery paylod in response.

Fix for multiple discovery paylod in response.

When consumer do discovery request to cloud,
cloud server can response on multiple device's result by one of response.
consumer service does not handle multiple discovery payload befour.

When applying this changes, consumer service can handle
multiple discovery payloads.

Change-Id: I516ac933daf435b436158ae4983f0ffedefe32c0
Signed-off-by: KIM JungYong <jyong2.kim@samsung.com>
Reviewed-on: https://gerrit.iotivity.org/gerrit/16469
Tested-by: jenkins-iotivity <jenkins@iotivity.org>
Reviewed-by: Uze Choi <uzchoi@samsung.com>