change_set_password() was changed to prefer TCP. However, because
UDP_LAST falls back to UDP after one second, we can still get a replay
error due to a dropped packet, before the TCP layer has a chance to
retry.
Instead, try k5_sendto() with NO_UDP, and only fall back to UDP after
TCP fails completely without reaching a server. In sendto_kdc.c,
implement an ONLY_UDP transport strategy to allow the UDP fallback.
Resolves: rhbz#2076965
Signed-off-by: Julien Rische <jrische@redhat.com>
