client, librados, osdc: do not shadow Dispatcher::cct

there is no need to have another `cct` as `Dispatch` has one already. and in `Objecter`, the ctor is initiating its parent class using the uninitialized member variable `cct`. it does not hurt since the `Dispatch::cct` in this case is never referenced. but the less uncertainty the better.
I understand why but it took me a few minutes to figure out ;-) It would be good to have that explicitly explained in the commit message.