mv_machine_learning: fix label removal issue of face recognition

mv_machine_learning: fix label removal issue of face recognition

[Issue type] : bug fix
[Version] : 0.28.16

Fix a label removal issue of face recognition framework.

Due to this issue, seg. fault happened when unregistering a given label
because the label table wan't updated after unregistering the label.

Therefore, this patch fixes the problem by making sure to update the label
table after unregistering. In addition, this patch makes the result CAPI
to be allowed after mv_face_recognition_inference function call so relevalt
test case is also updated properly.

Change-Id: Ib913d56c8b3625c2c6ebf9468aa19734d4ada0d2
Signed-off-by: Inki Dae <inki.dae@samsung.com>