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)

ticket: 7539
version_fixed: 1.11.1
status: resolved
Fix iprop safety net in kdb5_util load

The error message was missing a newline, and the exit behavior causes
the database to be destroyed.

(cherry picked from commit b264161818eba43263b4d7f137dbae6b266907f0)

ticket: 7370
version_fixed: 1.11.1
status: resolved
Check for negative poll timeout in k5_sendto_kdc

(cherry picked from commit 74bee54227deb64a41c2e79f57dd2a2c5ea010a3)

ticket: 7553
version_fixed: 1.11.1
status: resolved