Pass "type/name" to scheduler (fixes warnings)

IDataBroker::algorithmsRequiredFor has this unfortunate interface where TypeNameString is implicitly convertible from a string. Passing "abc" is equivalent to "abc/abc" which doesn't always make sense especially since the implementation in HiveDataBroker explicitly checks TypeNameString::type() for consistency.

  virtual std::vector<Gaudi::Algorithm*>
  algorithmsRequiredFor( const Gaudi::Utils::TypeNameString& alg,
                         const std::vector<std::string>&     stoppers = {} ) const = 0;

Here the usage of the interface is improved.

/cc @graven