Update locations of Gerrit's CLA text

Google has moved the CLA text to a new site.

Change-Id: If5f578d99c987f78a14aa7d674ea2d1a55735c2a
diff --git a/Documentation/dev-contributing.txt b/Documentation/dev-contributing.txt
index b4cae0d..ec3495d 100644
--- a/Documentation/dev-contributing.txt
+++ b/Documentation/dev-contributing.txt
@@ -16,8 +16,8 @@
 
 For reference, the actual agreements are linked below
 
-* https://gerrit-review.googlesource.com/static/cla_individual.html
-* https://gerrit-review.googlesource.com/static/cla_corporate.html
+* https://cla.developers.google.com/about/android-individual
+* https://source.android.com/source/cla-corporate.pdf
 
 As Gerrit is a code review tool, naturally contributions will
 be reviewed before they will get submitted to the code base.  To