update to android-5.1.0_r3

Change-Id: Idaf33aa9151ae8588746a82747180d1c60828d12
diff --git a/default.xml b/default.xml
index 17c071f..3540b5d 100644
--- a/default.xml
+++ b/default.xml
@@ -4,7 +4,7 @@
   <remote  name="aosp"
            fetch="https://android.googlesource.com"
            review="android-review.googlesource.com"
-           revision="refs/tags/android-5.1.0_r1" />
+           revision="refs/tags/android-5.1.0_r3" />
 
   <remote  name="github"
            fetch=".."