changed the test so if you add the define it compiles but the test fails anyways because it requires `riak_core_handoff_receiver/sender_sup`:

```
ring-resizing/riak_core $ ./rebar skip_deps=true eunit suite=riak_core_handoff_manager
==> riak_core (eunit)
src/riak_core_handoff_manager.erl:612: function add_outbound/4 undefined
ring-resizing/riak_core $ ./rebar skip_deps=true eunit suite=riak_core_handoff_manager
==> riak_core (eunit)
Compiled src/riak_core_handoff_manager.erl
riak_core_handoff_manager:603: handoff_test_...*skipped*
module 'riak_core_handoff_manager'
*unexpected termination of test process*
::{noproc,{gen_server,call,
                      [riak_core_handoff_receiver_sup,count_children,
                       infinity]}}
....
```