Fix wallpaper backup eligibility test

Bug 30970354
Bug 30938483

Change-Id: I3c933a80505238897ceb8e89c228ed48ee5a9d0e
diff --git a/services/core/java/com/android/server/wallpaper/WallpaperManagerService.java b/services/core/java/com/android/server/wallpaper/WallpaperManagerService.java
index 64f79e1..4983111 100644
--- a/services/core/java/com/android/server/wallpaper/WallpaperManagerService.java
+++ b/services/core/java/com/android/server/wallpaper/WallpaperManagerService.java
@@ -1757,8 +1757,8 @@
         }
 
         WallpaperData wallpaper = (which == FLAG_LOCK)
-                ? mWallpaperMap.get(userId)
-                : mLockWallpaperMap.get(userId);
+                ? mLockWallpaperMap.get(userId)
+                : mWallpaperMap.get(userId);
         return (wallpaper != null) ? wallpaper.allowBackup : false;
     }