Fix bug where loop variable was not enclosed in goroutine (fixes #188)
Fix bug where loop variable was not enclosed in goroutine (fixes #188)

matsuu/isucon6-final,isucon/isucon6-final,isucon/isucon6-final,matsuu/isucon6-final,matsuu/isucon6-final,isucon/isucon6-final,matsuu/isucon6-final,matsuu/isucon6-final,isucon/isucon6-final,isucon/isucon6-final,isucon/isucon6-final,matsuu/isucon6-final,isucon/isucon6-final,isucon/isucon6-final,matsuu/isucon6-final,matsuu/isucon6-final