fix quant_post batch_size (PaddlePaddle#1006)

Author: yghstill

paddleslim/quant/quanter.py

@@ -312,7 +312,7 @@ def quant_post_static(
         params_filename=None,
         save_model_filename='__model__',
         save_params_filename='__params__',
-        batch_size=16,
+        batch_size=1,
         batch_nums=None,
         scope=None,
         algo='hist',
@@ -359,7 +359,7 @@ def quant_post_static(
         save_model_filename(str): The name of model file to save the quantized inference program.  Default: '__model__'.
         save_params_filename(str): The name of file to save all related parameters. 
                 If it is set None, parameters will be saved in separate files. Default: '__params__'.
-        batch_size(int, optional): The batch size of DataLoader, default is 16.
+        batch_size(int, optional): The batch size of DataLoader, default is 1.
         batch_nums(int, optional): If batch_nums is not None, the number of calibrate 
                         data is 'batch_size*batch_nums'. If batch_nums is None, use all data
                         generated by sample_generator  as calibrate data.