TaskHub: emit taskAdded before adding the task to a document

As the adding to the document calls updateTaskLineNumber(), which will
emit a signal. The TaskModel needs to know the task before getting that
signal.

Task-number: QTCREATORBUG-7401

Change-Id: I35deba8696adc14199c6c56e45c414016e094088
Reviewed-by: Daniel Teske <daniel.teske@nokia.com>

src/plugins/projectexplorer/taskhub.cpp

@@ -110,10 +110,12 @@ void TaskHub::addTask(Task task)
         TaskMark *mark = new TaskMark(task.taskId, task.file.toString(), task.line, visible);
         mark->setIcon(taskTypeIcon(task.type));
         mark->setPriority(TextEditor::ITextMark::LowPriority);
-        mark->init();
         task.addMark(mark);
+        emit taskAdded(task);
+        mark->init();
+    } else {
+        emit taskAdded(task);
     }
-    emit taskAdded(task);
 }
 
 void TaskHub::clearTasks(const Core::Id &categoryId)