Clean up the import

app/src/main/java/com/hippo/ehviewer/ui/DirPickerActivity.java

@@ -23,12 +23,10 @@ import android.support.annotation.NonNull;
 import android.support.annotation.Nullable;
 import android.view.MenuItem;
 import android.view.View;
-import android.view.WindowManager;
 import android.widget.TextView;
 import android.widget.Toast;
 
 import com.hippo.ehviewer.R;
-import com.hippo.ehviewer.Settings;
 import com.hippo.ripple.Ripple;
 import com.hippo.widget.DirExplorer;
 import com.hippo.yorozuya.ViewUtils;