flush forcely if closure has fds

flush forcely if closure has fds

This patch is quite different with the original patch. The original patch did
two things. One is flushing forcely if closure has fds. Another is closing fds
remained in connection fds_in array.

Now closing fds is patched in wayland 1.15.0. So, we just remain the force flushing
patch.

Below is the original patch message

	[original patch message]

	commit d83694a742291e283f88b4db43ad5d9a9acf75bc
	Author: Sangjin Lee <lsj119@samsung.com>

		wayland-client: fix invalid fd about destroyed proxy

		If server sends fds but the proxy was destroyed,
		then that fds remain in connetion fds_in array.
		so they can be misused by other proxy.

		The simple solution is to separate the message including fds from the other messages
		and In queueing process in clients, if received message of proxy is invaild,
		just consume the fds_in array.

Change-Id: I07dd9cf87f2b8cf6265bdbdb046ed0593faaa89c