插件中的Activity嵌套Fragment崩溃

当插件中的Activity使用Fragment的时候崩溃找不到相应的Fragment
```
Unable to instantiate fragment com.xx.TestFragment: make sure class name exists, is public, and has an empty constructor that is public
```

**RePlugin version**:2.1.7

**Android compile SDK version**:2.1.7

**Android ROM**:原生6.0.1

