Follow up #429 Replication relay crash with background=true

Duplicate log_fd to STDOUT_FILENO on say_logrotate()

See also 0a1780cbb114f26e3d6b2dda500e48a3bb1eb469
Merge remote-tracking branch 'origin/fix-logrotate-in-background'
Merge branch 'master' of github.com:tarantool/tarantool