[gnome-system-monitor/migrateui] Fix build warning for string conversion

[Robert Roth <robertroth src gnome org>]

commit 1ada1adf92ec055ef9454d44444becfbf2cbb525
Author: Robert Roth <robert roth off gmail com>
Date:   Sat Jul 21 10:43:02 2012 +0300

    Fix build warning for string conversion

 src/procdialogs.cpp |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/src/procdialogs.cpp b/src/procdialogs.cpp
index 801d9f8..bbe956f 100644
--- a/src/procdialogs.cpp
+++ b/src/procdialogs.cpp
@@ -367,7 +367,7 @@ field_toggled (GtkCellRendererToggle *cell, gchar *path_str, gpointer data)
 }
 
 static void
-create_field_page(GtkBuilder* builder, GtkWidget *tree, gchar *widgetname)
+create_field_page(GtkBuilder* builder, GtkWidget *tree, const gchar *widgetname)
 {
     GtkTreeView *treeview;
     GList *it, *columns;