noexternallanglinks needs to be serialized

- there was a reason we serialized it...

LinksUpdate does array_diff_assoc.  If the property is set (as array), and compared
with empty property (a string), then we have a problem.

If the array values are strings, regardless if it's set or not then all is good.

Change-Id: Ie8796ebcc774b3c9aa91bc7c0555917ec66b66dd
Merge "noexternallanglinks needs to be serialized"