[glibmm] Interface: Move constructor: Add comment about not calling initialize_move().

[Murray Cumming <murrayc src gnome org>]

commit 0fae44475f7f04eb7e1f3c8209760dacf0063be2
Author: Murray Cumming <murrayc murrayc com>
Date:   Sat Aug 22 21:35:34 2015 +0200

    Interface: Move constructor: Add comment about not calling initialize_move().
    
    I am not entirely sure that this is the right thing to do.
    See my comment in the next commit about the test.

 glib/glibmm/interface.cc |    8 +++++++-
 1 files changed, 7 insertions(+), 1 deletions(-)
---
diff --git a/glib/glibmm/interface.cc b/glib/glibmm/interface.cc
index 609afe7..1f66c90 100644
--- a/glib/glibmm/interface.cc
+++ b/glib/glibmm/interface.cc
@@ -119,7 +119,13 @@ Interface::Interface()
 
 Interface::Interface(Interface&& src)
 : ObjectBase(std::move(src))
-{}
+{
+  //We don't call initialize_move() because we 
+  //want the derived move constructor to only cause it
+  //to be called once, so we just let it be called
+  //by the implementing class, such as Entry (implementing Editable).
+  //ObjectBase::initialize_move(src.gobject_, &src);
+}
 
 Interface& Interface::operator=(Interface&& src)
 {