[krbdev.mit.edu #8580] kinit fails for OTP users when using KdcProxy with both IPv4&6 DNS

[Greg Hudson via RT]

For TCP connections (without a proxy), if the KDC accepts the 
connection, we wait ten seconds before falling back to a different 
server.  Our intent was that this logic should also apply to TCP 
connections using a proxy, but it doesn't (because 
sendto_kdc.c:get_endtime() ignores connection state objects where state-
>addr.transport != TCP).  We can't fix that.

(For UDP, we have to retry pretty quickly because, unlike TCP, we get no 
indication that the KDC is alive and listening and got our request until 
it generates a response.  So UDP is incompatible with this kind of OTP 
deployment and there isn't really a good way around it without extending 
the protocol.)