initialize iter to zero in solver

Even though iter may not be meaningful if we are about to restore, it
can be useful before calling Solve or Step for the first time.

Author: longjon

src/caffe/solver.cpp

@@ -30,6 +30,7 @@ Solver<Dtype>::Solver(const string& param_file)
 template <typename Dtype>
 void Solver<Dtype>::Init(const SolverParameter& param) {
   initialized_ = false;
+  iter_ = 0;
   LOG(INFO) << "Initializing solver from parameters: " << std::endl
             << param.DebugString();
   param_ = param;