The '-T' parameter suffer some bugs, by the way of how smbldap-tools
handle parsing.

1) help and manpage say that -T parameter can have a list of email
 comma separated, but:

	smbldap-usermod -T "cristina,someaccount_at@gmail.com" cristina
	failed to modify entry: mailRoutingAddress: multiple values provided at /usr/sbin/smbldap-usermod line 617.

2) if i have to reset the email forwarding, i have to use:

	smbldap-usermod -T "," cristina

 if i use -T "" does nothing.


Both trouble arise from the fact that mailRoutingAddress are
single-valued, so have to take a string and not an array as input.


Quick patch/hack attached, that probably have to be adapted also for
smbldap-useradd (i've not tested).