Fix resources causing error with v21 toolset.
diff --git a/res/layout/preference_widget_seekbar.xml b/res/layout/preference_widget_seekbar.xml
index 324eb99..6f58823 100644
--- a/res/layout/preference_widget_seekbar.xml
+++ b/res/layout/preference_widget_seekbar.xml
@@ -56,7 +56,7 @@
             android:ellipsize="marquee"
             android:fadingEdge="horizontal" />
 
-        <TextView android:id="@+android:id/summary"
+        <TextView android:id="@android:id/summary"
             android:layout_width="wrap_content"
             android:layout_height="wrap_content"
             android:layout_below="@android:id/title"
@@ -66,7 +66,7 @@
             android:maxLines="4" />
 
         <!-- Preference should place its actual preference widget here. -->
-        <LinearLayout android:id="@+android:id/widget_frame"
+        <LinearLayout android:id="@android:id/widget_frame"
             android:layout_width="wrap_content"
             android:layout_height="match_parent"
             android:layout_below="@android:id/summary"
@@ -75,7 +75,7 @@
             android:gravity="center"
             android:orientation="vertical" />
 
-        <SeekBar android:id="@+android:id/seekbar2"
+        <SeekBar android:id="@+id/seekbar2"
             android:layout_width="match_parent"
             android:layout_height="wrap_content"
             android:layout_below="@android:id/summary"