Enable correct license checks.

BUG=b/166638163
TEST=`repo upload`

Change-Id: Ic559db1a56e0d189887eaeb433fdb367ba56d7ed
diff --git a/PRESUBMIT.cfg b/PRESUBMIT.cfg
index 8a1ba61..a3f1dfb 100644
--- a/PRESUBMIT.cfg
+++ b/PRESUBMIT.cfg
@@ -3,3 +3,4 @@
 
 [Hook Overrides]
 cros_license_check: false
+cos_license_check: true