smbd: Change logging when SET_OFFLINE is not supported

A client can send a request to set the OFFLINE attribute. In the default
code this is not supported and triggers a log message each time. Change
this to only log with level 0 when an actual errors occurs, and log
ENOTSUP with level 10.

Signed-off-by: Christof Schmitt <christof.schmitt@us.ibm.com>

Reviewed-by: Andrew Bartlett <abartlet@samba.org>

Autobuild-User(master): Andrew Bartlett <abartlet@samba.org>
Autobuild-Date(master): Thu Jun  6 04:30:26 CEST 2013 on sn-devel-104