Manifest for Android 8.1.0 Release 25 (OPM2.171019.029.A1)

Change-Id: I35fc03cb7499d88e50a6b008ebb1b18a1d265dc7
diff --git a/default.xml b/default.xml
index dd403f7..a1b5965 100644
--- a/default.xml
+++ b/default.xml
@@ -4,7 +4,7 @@
   <remote  name="aosp"
            fetch=".."
            review="https://android-review.googlesource.com/" />
-  <default revision="refs/tags/android-8.1.0_r20"
+  <default revision="refs/tags/android-8.1.0_r25"
            remote="aosp"
            sync-j="4" />