Add a test for locking and unlocking user accounts

Submitted by:	Robert O'Neil <oneil.rs@gmail.com>
Reviewed by:	will
Whitespace and comment tweaks, no functional changes.
Make it possible to do "iscsictl -Rt xxx -p yyy", to remove a session
that matches both -t and -p.

MFC after:	1 month
Sponsored by:	The FreeBSD Foundation