[gthumb] fixed warning

[Paolo Bacchilega <paobac src gnome org>]

commit 3e934d436de6c379b00e1f281fbaef9e4d58c067
Author: Paolo Bacchilega <paobac src gnome org>
Date:   Sun Jan 18 17:08:45 2015 +0100

    fixed warning

 gthumb/gth-filter-grid.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/gthumb/gth-filter-grid.c b/gthumb/gth-filter-grid.c
index 869f2e6..980ed7d 100644
--- a/gthumb/gth-filter-grid.c
+++ b/gthumb/gth-filter-grid.c
@@ -232,7 +232,7 @@ gth_filter_grid_init (GthFilterGrid *self)
        self->priv = G_TYPE_INSTANCE_GET_PRIVATE (self, GTH_TYPE_FILTER_GRID, GthFilterGridPrivate);
        self->priv->n_columns = DEFAULT_N_COLUMNS;
        self->priv->filter_ids = NULL;
-       self->priv->cell_data = g_hash_table_new_full (g_direct_hash, g_direct_equal, NULL, cell_data_free);
+       self->priv->cell_data = g_hash_table_new_full (g_direct_hash, g_direct_equal, NULL, (GDestroyNotify) 
cell_data_free);
        self->priv->active_button = NULL;
        self->priv->gp_data = NULL;
        self->priv->next_filter_id = 0;