mv_machine_learning: code cleanup for refactoring

mv_machine_learning: code cleanup for refactoring

Cleaned up mv_inference_open.cpp module for code refactoring.
What cleanups are,
	 - correct variable name which doesn't clarify what the name means.
	 - change goto label name to be meaningful with resource release issue.
	 - drop unnecessary code.
	 - move code so that relevant code could be grouped together.

This patch is just one step of what we have to for code refactoring.

Change-Id: Ia744508e0318d6558a0f4901a90d7ac8a14634e2
Signed-off-by: Inki Dae <inki.dae@samsung.com>