[planner] Remove deprecated gtk_style_unref.

[Luis Menina <lmenina src gnome org>]

commit b50c37ec28ae5b5460d079323ab671c8b63be6e4
Author: Luis Menina <liberforce freeside fr>
Date:   Sat Mar 2 21:10:49 2013 +0100

    Remove deprecated gtk_style_unref.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=575129

 src/planner-gantt-chart.c |    2 +-
 src/planner-usage-chart.c |    2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/src/planner-gantt-chart.c b/src/planner-gantt-chart.c
index a96ba2d..fe57100 100644
--- a/src/planner-gantt-chart.c
+++ b/src/planner-gantt-chart.c
@@ -545,7 +545,7 @@ gantt_chart_realize (GtkWidget *widget)
        colormap = gtk_widget_get_colormap (canvas);
        gdk_color_white (colormap, &style->bg[GTK_STATE_NORMAL]);
        gtk_widget_set_style (canvas, style);
-       gtk_style_unref (style);
+       g_object_unref (style);
 
        gantt_chart_set_zoom (chart, priv->zoom);
 }
diff --git a/src/planner-usage-chart.c b/src/planner-usage-chart.c
index a9db4f5..8c13671 100644
--- a/src/planner-usage-chart.c
+++ b/src/planner-usage-chart.c
@@ -651,7 +651,7 @@ usage_chart_realize (GtkWidget *widget)
        colormap = gtk_widget_get_colormap (canvas);
        gdk_color_white (colormap, &style->bg[GTK_STATE_NORMAL]);
        gtk_widget_set_style (canvas, style);
-       gtk_style_unref (style);
+       g_object_unref (style);
 
        usage_chart_set_zoom (chart, priv->zoom);
 }