I have reproduced this error. The magic happens in torchvision instead of pytorch version. ‘class VGG’ in //vision/torchvision/models/vgg.py has changed! The simple way is to update torchvision as @ptrblck metioned. Of course, you can update old vgg.py according to new version torchvision.
import torch
def __init__
    ...
    self.avgpool = nn.AdaptiveAvgPool2d((7,7))
    ...
def forward
    ...
    # x = x.view(x.size(0), -1)
    x = self.avgpool(x)
    x = torch.flatten(x, 1)
    ...

Both pytorch1.0 and 1.3 work well on my changes.
BTW, 尽量不要在目录中用中文，以避免不期望的行为