Change linespec_result::location to be an event_location_up

Change linespec_result::location to be an event_location_up

This is a follow-up to another patch.  It changes
linespec_result::location to be an event_location_up.

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

	* probe.c (parse_probes): Update.
	* location.h (delete_event_location): Don't declare.
	(event_location_deleter::operator()): Update.
	* location.c (event_location_deleter::operator()): Rename from
	delete_event_location.
	* linespec.h (linespec_result) <location>: Change type to
	event_location_up.
	* linespec.c (canonicalize_linespec, event_location_to_sals)
	(decode_objc): Update.
	(linespec_result): Don't call delete_event_location.
	* breakpoint.c (create_breakpoints_sal)
	(bkpt_probe_create_sals_from_location)
	(strace_marker_create_sals_from_location): Update.