加载xls时路径判断，如果空退出；

ssat_sdk/MenuTree3/TExcelParser.py

@@ -23,6 +23,9 @@ class CExcelParser(CBaseLog):
                 path = path.decode('utf-8')
             self.xls_path = path
 
+        if not os.path.exists(self.xls_path):
+            return
+
         # 打开文件;
         wb = xlrd.open_workbook(filename=self.xls_path)
         if wb is None: