Fix potential crash with malformed reports

If reports contain an opening <object> tag, but omit the closing tag,
the html string is freed and still used some time later.

git-svn-id: svn+ssh://svn.gnucash.org/repo/gnucash/trunk@22544 57a11ea4-9604-0410-9ed3-97b8803252fd

src/html/gnc-html-webkit.c

@@ -383,7 +383,7 @@ handle_embedded_object( GncHtmlWebkit* self, gchar* html_str )
                 Return the original html string because we can't properly parse it */
             g_free (classid_str);
             g_free (html_str_result);
-            return html_str;
+            return g_strdup (html_str);
         }
         end_object_tag += strlen( "</object>" );
         object_contents = g_strndup( object_tag, (end_object_tag - object_tag) );