Change group owner from update_engine to libchrome.

Bug: 33166666
Test: gerrit uploader
Change-Id: I69da51a7d79fab934cd87a85e88ebafca32836ae
diff --git a/OWNERS b/OWNERS
index 58e4fbe..b5b5d5f 100644
--- a/OWNERS
+++ b/OWNERS
@@ -1,6 +1,6 @@
 # Default code reviewers picked from top 3 or more developers.
 # Please update this list if you find better candidates.
-# used by system/update_engine
-include platform/system/update_engine:/OWNERS
+# used by libchrome
+include platform/external/libchrome:/OWNERS
 # previous importer
 armansito@google.com