Updated mediawiki/extensions
Project: mediawiki/extensions/CentralAuth  68314bd2567509e826f7fc9159e5a7eb7e2e16b5

Used empty string instead of null for lock in setglobalaccountstatus API

For this kind of unset value, no other API module uses null.
Also, null causes invalid XML from paraminfo.

Change-Id: I54295e81b68db44770aaf1f0e8df7d0a4d807505