Fix two pane background

src/main/res/layout/task_list_body_standard.xml

@@ -2,7 +2,6 @@
     xmlns:tools="http://schemas.android.com/tools"
     android:id="@+id/swipe_layout"
     style="@style/task_list_container"
-    android:background="?attr/asContentBackground"
     android:layout_width="fill_parent"
     android:layout_height="fill_parent"
     android:elevation="@dimen/elevation_task_list"

src/main/res/layout/task_list_body_subtasks.xml

@@ -2,7 +2,6 @@
     xmlns:tools="http://schemas.android.com/tools"
     android:id="@+id/swipe_layout"
     style="@style/task_list_container"
-    android:background="?attr/asContentBackground"
     android:layout_width="fill_parent"
     android:layout_height="wrap_content"
     android:elevation="@dimen/elevation_task_list"

src/main/res/values-w820dp/styles.xml

@@ -1,6 +1,7 @@
 <?xml version="1.0" encoding="utf-8"?>
 <resources xmlns:tools="http://schemas.android.com/tools">
     <style name="task_list_container">
+        <item name="android:background">?attr/asContentBackground</item>
         <item name="android:clipToPadding">false</item>
         <item name="android:paddingLeft">0dp</item>
         <item name="android:paddingStart" tools:ignore="NewApi">0dp</item>

src/main/res/values/styles.xml

@@ -108,7 +108,9 @@
         <item name="android:layout_gravity">end|bottom</item>
     </style>
 
-    <style name="task_list_container"/>
+    <style name="task_list_container">
+        <item name="android:background">?attr/asContentBackground</item>
+    </style>
 
     <style name="TextAppearance.Medium">
         <item name="android:textSize">18sp</item>