math_opt → gscip Relation

File in ortools/math_opt	Includes file in ortools/gscip
solvers / gscip_solver.cc	gscip.h
solvers / gscip_solver.cc	gscip_parameters.h
solvers / gscip_solver.h	gscip.h
solvers / gscip_solver_callback.cc	gscip_message_handler.h
solvers / gscip_solver_callback.h	gscip.h