* target.h (target_ops): Rename send_signal to request_interrupt,

	* target.h (target_ops): Rename send_signal to request_interrupt,
	and remove enum target_signal parameter.
	* linux-low.c (linux_request_interrupt): Rename from
	linux_send_signal, and always send SIGINT.
	* spu-low.c (spu_request_interrupt): Rename from spu_send_signal,
	and always send SIGINT.
	* remote-utils.c (putpkt_binary): Call request_interrupt, instead
	of send_signal.
	(input_interrupt): Likewise.