[gnote] Fix compiler warning

[Aurimas Černius <aurimasc src gnome org>]

commit b7ad2104e7e2adc4b81d32a11b0f0b74c5dd706a
Author: Aurimas Černius <aurisc4 gmail com>
Date:   Sun Mar 24 22:35:03 2019 +0200

    Fix compiler warning

 src/utils.cpp | 4 ++--
 src/utils.hpp | 4 ++--
 2 files changed, 4 insertions(+), 4 deletions(-)
---
diff --git a/src/utils.cpp b/src/utils.cpp
index 5206cf5d..1eaf4c72 100644
--- a/src/utils.cpp
+++ b/src/utils.cpp
@@ -1,7 +1,7 @@
 /*
  * gnote
  *
- * Copyright (C) 2010-2017 Aurimas Cernius
+ * Copyright (C) 2010-2017,2019 Aurimas Cernius
  * Copyright (C) 2010 Debarshi Ray
  * Copyright (C) 2009 Hubert Figuiere
  *
@@ -783,7 +783,7 @@ namespace gnote {
     }
 
 
-    bool InterruptableTimeout::callback(InterruptableTimeout* self)
+    int InterruptableTimeout::callback(InterruptableTimeout* self)
     {
       if(self)
         return self->timeout_expired();
diff --git a/src/utils.hpp b/src/utils.hpp
index 617aeedf..aaa9e3a8 100644
--- a/src/utils.hpp
+++ b/src/utils.hpp
@@ -1,7 +1,7 @@
 /*
  * gnote
  *
- * Copyright (C) 2011-2013,2015-2017 Aurimas Cernius
+ * Copyright (C) 2011-2013,2015-2017,2019 Aurimas Cernius
  * Copyright (C) 2009 Hubert Figuiere
  *
  * This program is free software: you can redistribute it and/or modify
@@ -230,7 +230,7 @@ namespace gnote {
       void cancel();
       sigc::signal<void> signal_timeout;
     private:
-      static bool callback(InterruptableTimeout*);
+      static int callback(InterruptableTimeout*);
       bool timeout_expired();
       guint m_timeout_id;
     };