examples/artik_examples: fix memory leak in cloud program
examples/artik_examples: fix memory leak in cloud program

The cloud program did not free the parsed JSON object after
use, which caused a memory leak to occur on each received message.
This patch fixe the leak by calling appropriate cleanup function.

Change-Id: I77c59d97b30d6b5c709e410b8b8de6a13c52fb98
Signed-off-by: Gregory Lemercier <8dfc97fc6edd815cc4739eb8e7c74f3c8222d00f@samsung.com>

JunhwanPark/TizenRT,JunhwanPark/TizenRT,JunhwanPark/TizenRT,JunhwanPark/TizenRT,JunhwanPark/TizenRT,JunhwanPark/TizenRT