Set initial values for default meta keys when loading images (#2281)
Set initial values for default meta keys when loading images (#2281)

* Set initial values for default meta keys when loading images

On branch set_default_metakeys
Changes to be committed:
modified:   mmdet/datasets/pipelines/loading.py

* Change local variable name

On branch set_default_metakeys
Changes to be committed:
modified:   mmdet/datasets/pipelines/loading.py
open-mmlab/mmdetection,open-mmlab/mmdetection