[Vala] Wrong glib-2.0 vapi

[yannick inizan <inizan yannick gmail com>]

Hi.

I've a problem with glib-2.0 vapi and OptionContext :

[Compact]
#if GLIB_2_44
[CCode (ref_function = "g_option_context_ref", unref_function =
"g_option_context_unref", type_id = "G_TYPE_OPTION_GROUP")]
#else
[CCode (free_function = "g_option_context_free")]
#endif
public class OptionContext {

g_option_context_unref doesn't exist, but free_function exists.
I've to copy vapi and remove this condition