refine logs, test=develop (#4642)

dygraph/similarity_net/model_check.py

@@ -36,10 +36,10 @@ def check_cuda(use_cuda, err = \
 
 def check_version():
     """
-        Log error and exit when the installed version of paddlepaddle is
-        not satisfied.
-        """
-    err = "PaddlePaddle version 1.6 or higher is required, " \
+    Log error and exit when the installed version of paddlepaddle is
+    not satisfied.
+    """
+    err = "PaddlePaddle version 1.8 or higher is required, " \
         "or a suitable develop version is satisfied as well. \n" \
         "Please make sure the version is good with your code." \
 
@@ -55,7 +55,7 @@ def check_version():
     Log error and exit when the installed version of paddlepaddle is
     not satisfied.
     """
-    err = "PaddlePaddle version 1.6 or higher is required, " \
+    err = "PaddlePaddle version 1.8 or higher is required, " \
         "or a suitable develop version is satisfied as well. \n" \
         "Please make sure the version is good with your code." \