Second attempt to fix a null pointer reference in deallocators of

built-in types (the first was in revision 21877).  When an exception
has raised within from the __init__ method of a user-defined class
derived from a built-in type (e.g., UnaryPredicate0D and
BinaryPredicate1D), some member variables of the base type are
left uninitialized, leading to a null pointer reference in the
"__dealloc__" function in the base type.  To avoid this, pointer
checking was added in the deallocators of those built-in types that
can be used to define a subclass by a user.

source/blender/freestyle/intern/python/BPy_Iterator.cpp

@@ -193,7 +193,8 @@ PyMODINIT_FUNC Iterator_Init( PyObject *module )
 
 void Iterator___dealloc__(BPy_Iterator* self)
 {
-	delete self->it;
+	if (self->it)
+		delete self->it;
     self->ob_type->tp_free((PyObject*)self);
 }