skipping pretraining network loading when downloading is unsuccessful (#3558)
skipping pretraining network loading when downloading is unsuccessful (#3558)

Signed-off-by: Wenqi Li <8ba7dfe933ef10910139377fbe2efeb7f8f88b49@nvidia.com>
Project-MONAI/MONAI,Project-MONAI/MONAI,Project-MONAI/MONAI,Project-MONAI/MONAI