lint: fix possible overdraw: Root element paints background @color/background_color with a theme that also paints a background (inferred theme is @style/Theme.ownCloud.Toolbar)

src/main/res/layout/file_details_empty.xml

@@ -20,7 +20,6 @@
 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
 	android:layout_width="match_parent"
 	android:layout_height="match_parent"
-    android:background="@color/background_color"
     android:orientation="vertical">
 
     <TextView