iSCSI: Minor Comment on CHAP_N

[Steve Senum <ssenum@cisco.com>]

Julian and Ofer,

At the last plugfest, Ayman said there seemed to be
some confusion about the CHAP_N key.  It would be helpful
to add a comment in section 10.1.4 to the effect of:

  The CHAP_N key specifies the identity of the iSCSI
  Initiator or Target for CHAP authentication purposes, which
  may be different from the iSCSI name and should be configurable.

I think a similiar comment applies to SRP_U key.

Regards,
Steve Senum