default vqa2/mutan_att_train example (also for demo) is messed

[dearkafka]

Model from http://data.lip6.fr/cadene/vqa.pytorch/vqa2/mutan_att_train.zip gives extremely confusing results, I suggest everyone trying another model, e.g.  http://webia.lip6.fr/~cadene/Downloads/vqa.pytorch/logs/vqa/mutan_att_trainval.zip which is on vqa (yaml is in vqa.pytorch/options/vqa/).