[Update] MobileNet-v1 load_pretrained_cnn function

When I tried to train the MobileNet-v1 pretrained model, I faced an error.
So, I fixed it.

Author: leaderj1001

lib/nets/mobilenet_v1.py

@@ -289,6 +289,5 @@ def set_bn_eval(m):
     def load_pretrained_cnn(self, state_dict):
         print('Warning: No available pretrained model yet')
         self.mobilenet.load_state_dict({
-            k: state_dict['features.' + k]
-            for k in list(self.mobilenet.state_dict())
+            k: state_dict['features.' + k] for k in list(self.mobilenet.state_dict()) if 'features.' + k in state_dict
         })