Manifest for Android P preview 1

Change-Id: Ide5c6058e3fc25f6a0dd9da1290451c98c34b3d6
diff --git a/default.xml b/default.xml
index e7b95f7..c07d414 100644
--- a/default.xml
+++ b/default.xml
@@ -4,7 +4,7 @@
   <remote  name="aosp"
            fetch=".."
            review="https://android-review.googlesource.com/" />
-  <default revision="master"
+  <default revision="refs/tags/android-p-preview-1"
            remote="aosp"
            sync-j="4" />