增加日志打印，排查错误

src/main/java/com/sagacloud/util/compute_engine/core/CoreComputeUtil.java

@@ -652,6 +652,7 @@ public class CoreComputeUtil {
             if ("expression".equals(output.mode)) {
                 if (output.expression != null) {
                     try {
+                        log.info("startExpression：{} ",output.expression);
                         output.root = String2Grammar.Generate(output.expression);
                     } catch (Exception e) {
                         log.error("Error expression:" + instance.object_sign + "_" + instance.instance_name + "\t" + output.output_sign + "\t"