操作json配置时先判断有无该字段，解决402卡死的问题

hgdriver/hgdev/hg_scanner.cpp

@@ -3373,6 +3373,8 @@ void hg_scanner::erase_option(const char* name)
 		jsn_children_.erase(it);
 }
 void hg_scanner::erase_range(const char* name, const char* opt_name)
+{
+	if (setting_jsn_.count(name) && setting_jsn_.at(name).count("range") > 0)
 	{
 		for (size_t i = 0; i < setting_jsn_.at(name).at("range").size(); i++)
 		{
@@ -3383,6 +3385,7 @@ void hg_scanner::erase_range(const char* name, const char* opt_name)
 			}
 		}
 	}
+}
 void hg_scanner::init_settings(const char* json_setting_text)
 {
 	const char* lang = language_option_descriptor();