(socketpair): Set socket type for both sockets.
From Egor Duda <deo@logos-m.ru>:
* fhandler.h (class fhandler_socket): New member to store socket type.
(fhandler_socket::get_socket_type): Access it.
(fhandler_socket::set_socket_type): Ditto.
* net.cc (cygwin_socket): Store socket type.
(cygwin_connect): Disable security checks for connectionless sockets.
(cygwin_accept): Ditto.