Suppress warnings caused by 'tput setaf' in non 256-color terminal emulators on OpenBSD

Sorry for second merge request, still learning how does GitLab work. I've just put the script onto my server and tested it on the tty and it surprised me with yet another errors.

Those two additional arguments seem to be required only in 256-color terminal emulators, on raw OpenBSD's console it will not show any colors and on "screen" it will complain about those two new arguments.

This commit should suppress any error caused by "tput setaf" arguments while still working fine on all terminal emulators.