fix log level and schema_file is a empty string issue

mindspore/ccsrc/minddata/dataset/util/status.cc

@@ -114,7 +114,9 @@ Status::Status(const StatusCode code, int line_of_code, const char *file_name, c
     ss << "File         : " << file_name << "\n";
   }
   err_msg_ = ss.str();
-  if (code == StatusCode::kUnexpectedError || code == StatusCode::kNetWorkError) {
+  if (code == StatusCode::kUnexpectedError) {
+    MS_LOG(ERROR) << err_msg_;
+  } else if (code == StatusCode::kNetWorkError) {
     MS_LOG(WARNING) << err_msg_;
   } else {
     MS_LOG(INFO) << err_msg_;

mindspore/dataset/engine/validators.py

@@ -842,6 +842,7 @@ def check_schema(method):
 
         if schema_file is not None:
             type_check(schema_file, (str,), "schema_file")
+            check_file(schema_file)
 
         return method(self, *args, **kwargs)