Fix default branch for r16 release branch.

Bug: http://b/64541024
diff --git a/default.xml b/default.xml
index b21e31d..1dd77d2 100644
--- a/default.xml
+++ b/default.xml
@@ -3,7 +3,7 @@
   <remote  name="aosp"
            fetch=".."
            review="https://android-review.googlesource.com/" />
-  <default revision="ndk-r16-release"
+  <default revision="ndk-release-r16"
            remote="aosp"
            sync-j="4" />
   <project path="bionic" name="platform/bionic" groups="presubmit" />