reader: Revert the changes to the VDL schema.

Change-Id: Idc46978cc060c952eb6ad65f0850c7676b373ca1
diff --git a/vdl/device-set.vdl b/vdl/device-set.vdl
index f803bae..c77dc5a 100644
--- a/vdl/device-set.vdl
+++ b/vdl/device-set.vdl
@@ -8,6 +8,7 @@
   DeviceId string
   Page int32
   Zoom int32
+  Linked bool
 }
 
 type DeviceSet struct {
diff --git a/vdl/file.vdl b/vdl/file.vdl
index 4c8b556..28ba384 100644
--- a/vdl/file.vdl
+++ b/vdl/file.vdl
@@ -14,5 +14,4 @@
   Title string
   Size int64
   Type string
-  DeviceSets map[string]DeviceSet
 }