Update get_data_from_XML.py

[abearman]

All objects in PASCAL VOC should only have one labeled ground truth bounding box. However, some objects (like 'person') have multiple "parts" labeled with bounding boxes (e.g., feet, hands). If you naively search the object XML path for the attribute 'bndbox' and take the last one (as the code was doing before), then you end up labeling some objects with a "part" bounding box (e.g., labeling only the foot of a person as 'person'!)

[yutaroyamanaka]

Thank you! Nice Improvement!