There is a problem if you try to dealloc a partially 
initialized heap allocated type object.  Because 
PyObject_GC_TRACK is not typically called until 
initialization is done, the gc_refs value is set to 
GC_UNTRACKED.

In type_dealloc, it calls _PyObject_GC_UNTRACK which 
skips the check to see if it is GC_UNTRACKED.

This patch fixes it so that it calls PyObject_GC_UnTrack 
to correctly handle this case.