[evolution] Workaround crash when pasting nothing into html message composer

[Milan Crha <mcrha src gnome org>]

commit 80d11c3d35bfb9fa716fa08ff0259098066f225e
Author: Milan Crha <mcrha redhat com>
Date:   Tue Nov 9 13:31:01 2010 +0100

    Workaround crash when pasting nothing into html message composer

 e-util/e-selection.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)
---
diff --git a/e-util/e-selection.c b/e-util/e-selection.c
index 3561dda..3d8922a 100644
--- a/e-util/e-selection.c
+++ b/e-util/e-selection.c
@@ -304,6 +304,8 @@ e_selection_data_get_html (GtkSelectionData *selection_data)
 	length = gtk_selection_data_get_length (selection_data);
 	data_type = gtk_selection_data_get_data_type (selection_data);
 
+	g_return_val_if_fail (data != NULL, NULL);
+
 	/* First validate the data.  Assume it's UTF-8 or UTF-16. */
 	if (g_utf8_validate ((const gchar *) data, length - 1, NULL))
 		utf8_text = g_strdup ((const gchar *) data);