Add type cast in construction of direct arg functor value.

Add a type cast to the code generated by ml_gen_direct_arg_deconstruct
to construct a value with a direct argument functor.  The cast exists in
the same code generated by ml_gen_direct_arg_construct.

compiler/ml_unify_gen.m:
	As above.
Add a NEWS section for 14.01.2.

NEWS:
	As above.