MINOR: cli: remove error message with 'set anon on|off'

Removed the error message in 'set anon on|off', it's more user
friendly: users use 'set anon on' even if the mode is already
activated, and the same for 'set anon off'. That allows users
to write the command line in the anonymized mode they want
without errors.

No backport needed, except if anonymization mechanism is backported.
1 file changed