[xwiki-users] how to fix "Unable to delete, rename any document or attachment from a subwiki using PostgreSQL" bug

Hello, I'm impacted by this bug on my fresh install off xWiki 5.3 "Unable to delete, rename any document or attachment from a subwiki using PostgreSQL" http://jira.xwiki.org/browse/XWIKI-9846 My question is simple: how can I patch my installation to fix this bug? Of course, I looking for "5.3.1 xwiki .war download" without success and I can't found the file to modify. I suppose I must use this file https://github.com/xwiki/xwiki-platform/blob/53079977a64f7d141e96e563f59e015... but where to put it? Java software and Tomcat server is new for me :-/ Thxs. Pascal B