Documentation: uncomment oem-setup

- Calamares complains if this isn't set, so the example should
  probably be 'safe' from that complaint. With 3.3 plans including
  'fatal error instead of warning' this should be fixed on-time.

settings.conf

@@ -166,7 +166,7 @@ dont-chroot: false
 # If this is set to true, Calamares refers to itself as a "setup program"
 # rather than an "installer". Defaults to the value of dont-chroot, but
 # Calamares will complain if this is not explicitly set.
-# oem-setup: true
+oem-setup: false
 
 # If this is set to true, the "Cancel" button will be disabled entirely.
 # The button is also hidden from view.