Change breakpoint event locations to event_location_up

Change breakpoint event locations to event_location_up

This is a follow-up to an earlier patch.  It changes breakpoint's
location and location_range_end members to be of type
event_location_up, then fixes up the users.

gdb/ChangeLog
2017-04-12  Tom Tromey  <tom@tromey.com>

	* remote.c (remote_download_tracepoint): Update.
	* python/py-breakpoint.c (bppy_get_location): Update.
	* guile/scm-breakpoint.c (bpscm_print_breakpoint_smob)
	(gdbscm_breakpoint_location): Update.
	* elfread.c (elf_gnu_ifunc_resolver_return_stop): Update.
	* breakpoint.h (struct breakpoint) <location, location_range_end>:
	Change type to event_location_up.
	* breakpoint.c (create_overlay_event_breakpoint)
	(create_longjmp_master_breakpoint)
	(create_std_terminate_master_breakpoint)
	(create_exception_master_breakpoint)
	(breakpoint_event_location_empty_p, print_breakpoint_location)
	(print_one_breakpoint_location, create_thread_event_breakpoint)
	(init_breakpoint_sal, create_breakpoint)
	(print_recreate_ranged_breakpoint, break_range_command)
	(init_ada_exception_breakpoint, say_where): Update.
	(base_breakpoint_dtor): Don't call delete_event_location.
	(bkpt_print_recreate, tracepoint_print_recreate)
	(dprintf_print_recreate, update_static_tracepoint)
	(breakpoint_re_set_default): Update.