PR remote/2154

	PR remote/2154
	* remote.c (remote_thread_alive): Remove local buf.
	(remote_get_threadinfo): Remove local threadinfo_pkt.
	(remote_get_threadlist): Remove unused threadlist_packet.
	(remote_current_thread): Remove local buf.
	(remote_threads_info): Set bufp after getpkt.
	(remote_threads_extra_info): Remove local bufp.
	(get_offsets): Set buf after getpkt.
	(remote_check_symbols): Set reply after getpkt.
	(remote_vcont_probe): Set buf after getpkt.
	(remote_resume): Set buf after set_thread.
	(remote_wait, remote_async_wait): Set buf after getpkt.
	(fetch_register_using_p): Set buf after remote_send.
	(remote_fetch_registers): Likewise.
	(store_register_using_P): Don't use buf after remote_send.
	(check_binary_download, remote_write_bytes)
	(remote_read_bytes, remote_rcmd): Remove local buf.