[dia] Don't use deprecated function gdk_drawable_unref().

[Hans Breuer <hans src gnome org>]

commit 81b76fc754e50c2aae431678e1c82e678bb1c205
Author: Adam Buchbinder <adam buchbinder gmail com>
Date:   Mon May 4 12:11:59 2009 -0400

    Don't use deprecated function gdk_drawable_unref().
    
    Replaced gdk_drawable_unref() with g_object_unref():
    http://library.gnome.org/devel/gdk/stable/gdk-Drawing-Primitives.html#gdk-drawable-unref
    
    Signed-off-by: Adam Buchbinder <adam buchbinder gmail com>
    Signed-off-by: Hans Breuer <hans breuer org>
---
 app/render_gdk.c                      |    2 +-
 plug-ins/cairo/diacairo-interactive.c |    2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/app/render_gdk.c b/app/render_gdk.c
index 60ccb7a..a96f54f 100644
--- a/app/render_gdk.c
+++ b/app/render_gdk.c
@@ -101,7 +101,7 @@ set_size(DiaRenderer *object, gpointer window,
   DiaGdkRenderer *renderer = DIA_GDK_RENDERER (object);
 
   if (renderer->pixmap != NULL)
-    gdk_drawable_unref(renderer->pixmap);
+    g_object_unref(renderer->pixmap);
 
   if (window)
     renderer->pixmap = gdk_pixmap_new(GDK_WINDOW(window),  width, height, -1);
diff --git a/plug-ins/cairo/diacairo-interactive.c b/plug-ins/cairo/diacairo-interactive.c
index 65f6512..3888280 100644
--- a/plug-ins/cairo/diacairo-interactive.c
+++ b/plug-ins/cairo/diacairo-interactive.c
@@ -330,7 +330,7 @@ set_size(DiaRenderer *object, gpointer window,
   renderer->width = width;
   renderer->height = height;
   if (renderer->pixmap != NULL)
-    gdk_drawable_unref(renderer->pixmap);
+    g_object_unref(renderer->pixmap);
 
   /* TODO: we can probably get rid of this extra pixmap and just draw directly to what gdk_cairo_create() gives us for the window */
   renderer->pixmap = gdk_pixmap_new(GDK_WINDOW(window),  width, height, -1);