[LayaAir 2.0]Mac上面导出Xcode项目，文件损毁

Native版本：release-v2.7.0
IDE版本：2.7.1
打出的xcodeporj项目打开提示：The project "xx" is damaged and cannot be opened due to a parse error. Examine the project file for invalid edits or unresolved source control conflicts
新建的空项目直接打包出来就这样了。