Fixing wrong preference file name in LauncherFiles

Bug: 27778623
Change-Id: I28aa6698d3caa1fc11b2e8df0733143865f9b408
(cherry picked from commit 8a6edce064c1854895a91f120a42ccdc2f7804bb)
diff --git a/src/com/android/launcher3/LauncherFiles.java b/src/com/android/launcher3/LauncherFiles.java
index c08cd0b..6ce2293 100644
--- a/src/com/android/launcher3/LauncherFiles.java
+++ b/src/com/android/launcher3/LauncherFiles.java
@@ -34,7 +34,7 @@
             WALLPAPER_CROP_PREFERENCES_KEY + XML,
             WALLPAPER_IMAGES_DB,
             WIDGET_PREVIEWS_DB,
-            MANAGED_USER_PREFERENCES_KEY,
+            MANAGED_USER_PREFERENCES_KEY + XML,
             APP_ICONS_DB));
 
     // TODO: Delete these files on upgrade