Fix no_host_referral concatention in KDC

If no_host_referral is set in both [kdcdefaults] and the realm
subsection, we're supposed to concatenate their values.  But the logic
in handle_referral_params would overwrite the value with the
non-concatenated realm value.  Similar bugs of this nature were fixed
in 639c9d0f5a7c68dc98a2a452abc05ca32443cddf (r22037) but this one was
missed.

(cherry picked from commit 6338d039cbd0b138642e3b123ac58dc802d1d907)

https://github.com/krb5/krb5/commit/8b03510d5e919ce2047b64d9a4b4d3a9fe6a07a4
Author: Greg Hudson <ghudson@mit.edu>
Committer: Tom Yu <tlyu@mit.edu>
Commit: 8b03510d5e919ce2047b64d9a4b4d3a9fe6a07a4
Branch: krb5-1.10
 src/kdc/main.c |   13 +++++++------
 1 files changed, 7 insertions(+), 6 deletions(-)