Update KUnit upstream branch

At the time of writing, KUnit was in linux-kselftest/next; now it is
being staged in a directory called linux-kselftest/test. Reflect that
change in the documentation.

Signed-off-by: Brendan Higgins <brendanhiggins@google.com>
Change-Id: I4464c48f6fffc4dee66e8a0e137fbccf8492832e
diff --git a/third_party/kernel/index.rst b/third_party/kernel/index.rst
index 7d7169a..05d1bdb 100644
--- a/third_party/kernel/index.rst
+++ b/third_party/kernel/index.rst
@@ -9,7 +9,7 @@
 Where to get the code
 ---------------------
 
-https://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest.git/log/?h=next
+https://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest.git/log/?h=test
 
 Getting Started Guide
 ---------------------