serializer: ensure backwards compatibility

app/task/project/load/load.cpp

@@ -37,7 +37,9 @@ bool ProjectLoadTask::Run()
 
   project_->set_filename(GetFilename());
 
-  ProjectSerializer::Result result = ProjectSerializer::Load(project_, GetFilename(), QStringLiteral("project"));
+  ProjectSerializer::Result result = ProjectSerializer::Load(project_, GetFilename(), ProjectSerializer::kProject);
+
+  layout_ = result.GetLoadData().layout;
 
   switch (result.code()) {
   case ProjectSerializer::kSuccess:

app/task/project/load/loadbasetask.h

@@ -50,11 +50,11 @@ public:
 protected:
   Project* project_;
 
+  MainWindowLayoutInfo layout_;
+
 private:
   QString filename_;
 
-  MainWindowLayoutInfo layout_;
-
 };
 
 }