util: WSAEWOULDBLOCK on connect should map to EINPROGRESS

util: WSAEWOULDBLOCK on connect should map to EINPROGRESS

In general, WSAEWOULDBLOCK can be mapped to EAGAIN as done by
socket_error() (or EWOULDBLOCK). But for connect() with non-blocking
sockets, it actually means the operation is in progress:

https://docs.microsoft.com/en-us/windows/win32/api/winsock2/nf-winsock2-connect
"The socket is marked as nonblocking and the connection cannot be completed immediately."

(this is also the behaviour implemented by GLib GSocket)

This fixes socket_can_bind_connect() test on win32.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>