Fix possible memory leak condition in PPM for Tizen Platform.

Fix possible memory leak condition in PPM for Tizen Platform.

API app_get_id allocates memory internally, which was not freed
resulting in possible memory leak.

Signed-off-by: Satya Prakash Gupta <sp.gupta@samsung.com>
Change-Id: Ibc2cc77ebe803f174ab5e7ec5cff18e54178f2a8
Reviewed-on: https://gerrit.iotivity.org/gerrit/1239
Reviewed-by: Madan Lanka <lanka.madan@samsung.com>
Reviewed-by: Harish Marappa <h.marappa@samsung.com>
Reviewed-by: Uze Choi <uzchoi@samsung.com>
Tested-by: Uze Choi <uzchoi@samsung.com>