[PATCH, libstdc++] Add the logistic distribution as an extension

[Paolo Carlini]

.. I have another comment: are we sure the usual strategy:

       template<typename _UniformRandomNumberGenerator>
     result_type
     operator()(_UniformRandomNumberGenerator& __urng)
     { return this->operator()(__urng, this->_M_param); }

doesn't make sense here too?

Paolo.