Force output of "crm configure show" to not use colors

We don't care about colors, we just want to parse plain text.

This allows us to avoid being hit by this crmsh bug:
https://bugzilla.novell.com/show_bug.cgi?id=893011

(cherry picked from commit a3524fbcce943887d4d80ee0c587447c4c4fd0d9)