Fix crash.

Summary: i.remove() makes i.key() crash. Duh.

Reviewers: #plasma, davidedmundson

Subscribers: plasma-devel

Tags: #plasma

Differential Revision: https://phabricator.kde.org/D4651

libtaskmanager/xwindowtasksmodel.cpp

@@ -314,8 +314,8 @@ void XWindowTasksModel::Private::transientChanged(WId window, NET::Properties pr
                 i.next();
 
                 if (i.value() == window) {
-                    i.remove();
                     oldLeader = i.key();
+                    i.remove();
                 }
             }