This removes make_bpstat_clear_actions_cleanup, replacing it with uses
of scope_exit.

gdb/ChangeLog:
2019-01-23  Tom Tromey  <tom@tromey.com>
	    Andrew Burgess  <andrew.burgess@embecosm.com>
	    Pedro Alves  <palves@redhat.com>

	* infrun.c (fetch_inferior_event): Use scope_exit.
	* utils.h (make_bpstat_clear_actions_cleanup): Don't declare.
	* top.c (execute_command): Use scope_exit.
	* breakpoint.c (bpstat_do_actions): Use scope_exit.
	* utils.c (do_bpstat_clear_actions_cleanup)
	(make_bpstat_clear_actions_cleanup): Remove.