application: Append a / to the icon resource path

g_resources_enumerate_children expects the path to end
in a '/' (even though thats not stated in the docs), and
will copy it if that isn't the case. Avoid the copy
by putting  a '/' there to begin with.

gtk/gtkapplication.c

@@ -204,7 +204,7 @@ gtk_application_load_resources (GtkApplication *application)
     gchar *iconspath;
 
     default_theme = gtk_icon_theme_get_default ();
-    iconspath = g_strconcat (base_path, "/icons", NULL);
+    iconspath = g_strconcat (base_path, "/icons/", NULL);
     gtk_icon_theme_add_resource_path (default_theme, iconspath);
     g_free (iconspath);
   }