test server kill skt with minus 1

The client spams the server with mirror protocol content
and then closes the connection.  However the server wants to
send that content back to all the mirror protocol
connections, including the one that closed.

The result is during the send back phase we usually see an
error trying to send to the close client connection. Because
we don't return -1, we don't close it on server side and the
error repeats a lot before finally closing.  This is a side-
effect of a recent patch to drain pending input before
really closing a dead connection.

This patch just changes it to return -1 on the failed send
attempt assertively closing the connection.

Signed-off-by: Andy Green <andy.green@linaro.org>
handle http union transition properly

There's no proper transition to http union state until now.

It only becomes apparant there's a problem when you try to
return -1 from the HTTP callback, during the close action
it will try to close() a nonsense, nonzero fd pointer in
the uninitialized u.http union member.

This patch takes a copy of the allocated headers struct from
the u.hdr union state, transitions to u.http clearing down u
and then calls the HTTP callback with URI args pointing to
the still-in-scope ah allocation.  After the call, the copy ah
is freed.

That makes sure we are in the correct union state while still
giving the HTTP callback access to the URI without having to
copy it around.

Reported-by: Edwin can den Oetelaar <oetelaar.automatisering@gmail.com>
Signed-off-by: Andy Green <andy.green@linaro.org>