Don't put special characters in SLOF

When SLOF is used by OBS, putting control characters breaks log. It
becomes binary file instead of just plain text

Signed-off-by: Dinar Valeev <dvaleev@suse.com>
Don't add colors to SLOF

Making output fancy breaks stuff too.

Signed-off-by: Dinar Valeev <dvaleev@suse.com>