MFC 273583:

Tidy up the login code; no functional changes.

Sponsored by:	The FreeBSD Foundation
MFC r273584:

Make the initiator-name and initiator-portal checks a little nicer.

Sponsored by:	The FreeBSD Foundation
MFC r273467:

Comment out parts about iSER; it's not implemented.

Sponsored by:	The FreeBSD Foundation
MFC r273470:

Fix ctl.conf example to use proper paths to ZVOLs.

Sponsored by:	The FreeBSD Foundation
MFC r273585:

Improve ctld.conf example.

Sponsored by:	The FreeBSD Foundation