Fix hop in dyn_hop_proposal.cpp

[foxtran]

In one of variants of hop function, initstate variable is not defined. After some looking, I've noticed that hop(int initstate, std::vector<double> &, double) is exactly the same hop(std::vector<double> &, double). In several places, where first variant of routine is called, initstate is 0, so I decided to call hop(int initstate, std::vector<double> &, double) from hop(std::vector<double> &, double) with initstate = 0. So, it should act as it was before.