Switch to system/core/janitors as OWNERS.

Change-Id: I3bb0830068f2fb8daaf07b877bad2adf84487c81
diff --git a/OWNERS b/OWNERS
index 682a067..7529cb9 100644
--- a/OWNERS
+++ b/OWNERS
@@ -1 +1 @@
-enh@google.com
+include platform/system/core:/janitors/OWNERS