lint: fix the resource R.layout.list_fragment_expandable appears to be unused

src/main/res/layout/list_fragment_expandable.xml

@@ -1,38 +0,0 @@
-<?xml version="1.0" encoding="utf-8"?>
-<!-- 
-This must be a clone of list_fragment.xml 
-
-EXCEPT: ExpandableListView must be used for @+id/swipe_refresh_files_emptyView
- -->
-<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
-	android:layout_width="@dimen/zero"
-	android:layout_height="match_parent"
-	android:layout_weight="1" >
-
-    <android.support.v4.widget.SwipeRefreshLayout
-        android:id="@+id/swipe_refresh_files"
-        android:layout_width="match_parent"
-        android:layout_height="match_parent" >
-
-        <ExpandableListView 
-            android:id="@+id/list_root"
-            android:layout_width="match_parent"
-            android:layout_height="match_parent" />
-        
-    </android.support.v4.widget.SwipeRefreshLayout>
-
-    <android.support.v4.widget.SwipeRefreshLayout
-        android:id="@+id/swipe_refresh_files_emptyView"
-        android:layout_width="match_parent"
-        android:layout_height="match_parent"
-        android:visibility="gone" >
-
-        <ScrollView
-            android:layout_width="match_parent"
-            android:layout_height="match_parent" >
-
-			<include layout="@layout/empty_list" />
-
-        </ScrollView>
-    </android.support.v4.widget.SwipeRefreshLayout>
-</FrameLayout>