[Fit API] move estimator to contrib

tests/nightly/estimator/test_estimator_cnn.py

@@ -22,7 +22,7 @@
 import mxnet as mx
 from mxnet import gluon, init, nd
 from mxnet.gluon import data
-from mxnet.gluon.estimator import estimator
+from mxnet.contrib.estimator import estimator
 from mxnet.gluon.model_zoo import vision
 
 def load_data_mnist(batch_size, resize=None, num_workers=4):

tests/nightly/estimator/test_sentiment_rnn.py

@@ -29,7 +29,7 @@
 from mxnet import nd, gluon
 from mxnet.contrib import text
 from mxnet.gluon import nn, rnn
-from mxnet.gluon.estimator import estimator
+from mxnet.contrib.estimator import estimator
 
 
 class TextCNN(nn.Block):

tests/python/unittest/test_gluon_estimator.py

@@ -24,7 +24,7 @@
 import mxnet as mx
 from mxnet import gluon
 from mxnet.gluon import nn
-from mxnet.gluon.estimator import Estimator, EventHandler
+from mxnet.contrib.estimator import Estimator, EventHandler
 from nose.tools import assert_raises
 
 

tests/python/unittest/test_gluon_event_handler.py

@@ -20,7 +20,7 @@
 import mxnet as mx
 from mxnet import nd
 from mxnet.gluon import nn, loss
-from mxnet.gluon.estimator import estimator, event_handler
+from mxnet.contrib.estimator import estimator, event_handler
 
 def _get_test_network():
     net = nn.Sequential()