Move notif_queue and remote_async_get_pending_events_token to remote_state

Move notif_queue and remote_async_get_pending_events_token to remote_state

This patch also removes notif_xfree, and don't pass it QUEUE_alloc, because
we don't have to free notif_client when the remote_notif_state is freed.

gdb:

2013-10-04  Yao Qi  <yao@codesourcery.com>

	* remote-notif.c (DECLARE_QUEUE_P): Remove.
	(notif_queue): Remove.
	(remote_notif_process): Add one parameter 'notif_queue'.
	Update comments.  Callers update.
	(remote_async_get_pending_events_token): Remove.
	(remote_notif_register_async_event_handler): Remove.
	(remote_notif_unregister_async_event_handler): Remove.
	(handle_notification): Add parameter 'notif_queue'.  Update
	comments.  Callers update.
	(notif_xfree): Remove.
	(remote_notif_state_allocate): New function.
	(remote_notif_state_xfree): New function.
	(_initialize_notif): Remove code to allocate queue.
	* remote-notif.h (DECLARE_QUEUE_P): Moved from remote-notif.c.
	(struct remote_notif_state): New.
	(handle_notification): Update declaration.
	(remote_notif_process): Likewise.
	(remote_notif_register_async_event_handler): Remove.
	(remote_notif_unregister_async_event_handler): Remove.
	(remote_notif_state_allocate): Declare.
	(remote_notif_state_xfree): Declare.
	* remote.c (struct remote_state) <notif_state>: New field.
	(remote_close): Don't call
	remote_notif_unregister_async_event_handler.  Call
	remote_notif_state_xfree.
	(remote_open_1): Don't call
	remote_notif_register_async_event_handler.  Call
	remote_notif_state_allocate.