Proposed Behavior change: don't fail when krb5_sname_to_principal cannot canonicalize input

[Greg Hudson]

I'm not really opposed to this, although one could argue that
host/foo.searchdomain is a better guess than host/foo in the absence of
DNS (when foo contains no dots).  But that assumes we can find out the
search domain (which might be easier than we used to think, but we don't
have a facility for it at the moment) and begs the question of what
happens when there are multiple search domains.