mv_machine_learning: code refactoring to GetPoseLandmarkDetectionResults function

mv_machine_learning: code refactoring to GetPoseLandmarkDetectionResults function

Did code refactoring to GetPoseLandmarkDetectionResults function of
Inference class by dropping Inference class dependency to mPoseResult object.

What this path did are,
	 - use smart pointer instead of new operator, and make postResult
	   object to be valid only in mv_inference_pose_landmark_detect_open
	   function context.
	 - drop some unnecessary local variables.
	 - and code sliding.

The biggest change of this patch is to drop Inference class dependency
of mPoseResult object for next code refactoring. As as result,
it drops one brace from GetPoseLandmarkDetectionResults function and makes
the function to be more simplified for code readability enhancement.

Change-Id: I25d1a175571d407404c088713a14e485496b2920
Signed-off-by: Inki Dae <inki.dae@samsung.com>