server: Fix possible wl_display_add_socket_fd memleak
server: Fix possible wl_display_add_socket_fd memleak

If wl_event_loop_add_fd failed, the fail path didn't free the
newly allocated struct wl_socket.
Reviewed-by: Derek Foreman <2f97e0f0bc172406aab8ccd42dab54c95bab8759@osg.samsung.com>

sir-murray/wayland,sir-murray/wayland,mchalupa/wayland,sir-murray/wayland,mchalupa/wayland,mchalupa/wayland