!1291 add import ckpt

Merge pull request !1291 from meixiaowei/master

example/resnet101_imagenet2012/README.md

@@ -87,7 +87,7 @@ sh run_distribute_train.sh rank_table_8p.json dataset/ilsvrc ./ckpt/pretrained.c
 # standalone training example（1p）
 sh run_standalone_train.sh dataset/ilsvrc
 
-f you want to load pretrained ckpt file,
+If you want to load pretrained ckpt file,
 sh run_standalone_train.sh dataset/ilsvrc ./ckpt/pretrained.ckpt
 ```
  

example/resnet101_imagenet2012/train.py

@@ -28,6 +28,7 @@ from mindspore.nn.optim.momentum import Momentum
 from mindspore.train.model import Model, ParallelMode
 from mindspore.train.callback import ModelCheckpoint, CheckpointConfig, LossMonitor, TimeMonitor
 from mindspore.train.loss_scale_manager import FixedLossScaleManager
+from mindspore.train.serialization import load_checkpoint, load_param_into_net
 import mindspore.dataset.engine as de
 from mindspore.communication.management import init
 import mindspore.nn as nn