[glibmm] Object: build fix

[Marcin Kolny <mkolny src gnome org>]

commit 0f1c2b720e9fe3210d2fd39593d5695a24197de4
Author: Marcin Kolny <marcin kolny gmail com>
Date:   Sun Jul 30 14:47:57 2017 +0100

    Object: build fix
    
    Value_Pointer class takes only one template argument

 glib/glibmm/object.h |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/glib/glibmm/object.h b/glib/glibmm/object.h
index 72c6692..006d5ea 100644
--- a/glib/glibmm/object.h
+++ b/glib/glibmm/object.h
@@ -233,9 +233,9 @@ struct TypeTraits<Glib::RefPtr<const T>>
 
 } // namespace Container_Helpers
 
-template <class T, class PtrT>
+template <class PtrT>
 inline PtrT
-Value_Pointer<T, PtrT>::get_(Glib::Object*) const
+Value_Pointer<PtrT>::get_(Glib::Object*) const
 {
   return dynamic_cast<T*>(get_object());
 }