Removing need to import saver_pb2 inside restore function

Author: ilblackdragon

skflow/estimators/base.py

@@ -386,8 +386,7 @@ def _restore(self, path):
             if not os.path.exists(saver_filename):
                 raise ValueError("Restore folder doesn't contain saver defintion.")
             with open(saver_filename) as fsaver:
-                from tensorflow.python.training import saver_pb2
-                saver_def = saver_pb2.SaverDef()
+                saver_def = tf.python.training.saver_pb2.SaverDef()
                 text_format.Merge(fsaver.read(), saver_def)
                 self._saver = tf.train.Saver(saver_def=saver_def)