wbinfo: Improve the wording for --online-status

wbinfo: Improve the wording for --online-status

Currently it displays if a domain is online or offline which is wrong.
It tells us if we maintain an active connection to the domain or not.

Users are confused if they read offline because the think winbind is not
functional with that domain.

Signed-off-by: Andreas Schneider <asn@samba.org>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>
Autobuild-User(master): Andrew Bartlett <abartlet@samba.org>
Autobuild-Date(master): Fri Mar 16 14:46:43 CET 2018 on sn-devel-144