User logout query changed to null by default and then it is not called at all. It causes problems on the installations which don't define this query and use a different database structure.
User logout query changed to null by default and then it is not called at all. It causes problems on the installations which don't define this query and use a different database structure.

git-svn-id: 4a0daf30c0bbd291b3bc5fe8f058bf11ee523347@1454 7d282ba1-3ae6-0310-8f9b-c9008a0864d2

fanout/tigase-server,f24-ag/tigase,amikey/tigase-server,amikey/tigase-server,fanout/tigase-server,f24-ag/tigase,nate-sentjens/tigase-xmpp-java,pivotal-nathan-sentjens/tigase-xmpp-java,pivotal-nathan-sentjens/tigase-xmpp-java,Smartupz/tigase-server,cgvarela/tigase-server,caiyingyuan/tigase71,nate-sentjens/tigase-xmpp-java,pivotal-nathan-sentjens/tigase-xmpp-java,fanout/tigase-server,amikey/tigase-server,wangningbo/tigase-server,pivotal-nathan-sentjens/tigase-xmpp-java,sourcebits-praveenkh/Tagase,f24-ag/tigase,wangningbo/tigase-server,sourcebits-praveenkh/Tagase,f24-ag/tigase,cgvarela/tigase-server,Smartupz/tigase-server,nate-sentjens/tigase-xmpp-java,nate-sentjens/tigase-xmpp-java,Smartupz/tigase-server,cgvarela/tigase-server,wangningbo/tigase-server,pivotal-nathan-sentjens/tigase-xmpp-java,cgvarela/tigase-server,fanout/tigase-server,wangningbo/tigase-server,Smartupz/tigase-server,nate-sentjens/tigase-xmpp-java,amikey/tigase-server,cgvarela/tigase-server,Smartupz/tigase-server,wangningbo/tigase-server,pivotal-nathan-sentjens/tigase-xmpp-java,sourcebits-praveenkh/Tagase,caiyingyuan/tigase71,sourcebits-praveenkh/Tagase,wangningbo/tigase-server,fanout/tigase-server,f24-ag/tigase,f24-ag/tigase,cgvarela/tigase-server,sourcebits-praveenkh/Tagase,caiyingyuan/tigase71,amikey/tigase-server,Smartupz/tigase-server,caiyingyuan/tigase71,caiyingyuan/tigase71,caiyingyuan/tigase71,wangningbo/tigase-server,sourcebits-praveenkh/Tagase,amikey/tigase-server,nate-sentjens/tigase-xmpp-java,fanout/tigase-server