Foundation copyrights, approved by emaste@. It does not include
files which carry other people's copyrights; if you're one
of those people, feel free to make similar change.
Reviewed by: emaste, imp, gbe (manpages)
Differential Revision: https://reviews.freebsd.org/D26980
While all tested initiators and targets use hex-encoded CHAP data, RFC also
allows base64 encoding there, and Microsoft certificaition tool uses it.
Reviewed by: trasz (earlier version)
MFC after: 2 weeks
Sponsored by: iXsystems, Inc.