Fix bug SQL query when checking if user is event host
Fix bug SQL query when checking if user is event host

MySQL doesn't match null values when filtering for column!="value".

Signed-off-by: Ivan Habunek <a15f8b81a160b4eebe5c84e9e3b65c87b9b2f18e@habunek.com>

lornajane/joindin-api,heiglandreas/joindin-api,dstockto/joindin-api,lornajane/joindin-api,asgrim/joindin-api,asgrim/joindin-api,heiglandreas/joindin-api,dstockto/joindin-api,railto/joindin-api,akrabat/joindin-api,heiglandreas/joindin-api,joindin/joindin-api,railto/joindin-api,railto/joindin-api,joindin/joindin-api,lornajane/joindin-api,joindin/joindin-api,akrabat/joindin-api,dstockto/joindin-api,akrabat/joindin-api,asgrim/joindin-api