perf thread: Fix reference count initial state

We should always return from thread__new(), the constructor, with the
object with a reference count of one, so that:

     struct thread *thread = thread__new();
     thread__put(thread);

Will call thread__delete().

If any reference is made to that 'thread' variable, it better use
thread__get(thread) to hold a reference.

We were returning with thread->refcnt set to zero, fix it and some cases
where thread__delete() was being called, which were not a problem
because just one reference was being used, now that we set it to 1, use
thread__put() instead.

Reported-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-4b9mkuk66to4ecckpmpvqx6s@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/tools/perf/util/intel-pt.c b/tools/perf/util/intel-pt.c
index 97f963a..81a2eb7 100644
--- a/tools/perf/util/intel-pt.c
+++ b/tools/perf/util/intel-pt.c
@@ -1744,7 +1744,7 @@
 	auxtrace_heap__free(&pt->heap);
 	intel_pt_free_events(session);
 	session->auxtrace = NULL;
-	thread__delete(pt->unknown_thread);
+	thread__put(pt->unknown_thread);
 	free(pt);
 }
 
@@ -2153,7 +2153,7 @@
 	return 0;
 
 err_delete_thread:
-	thread__delete(pt->unknown_thread);
+	thread__zput(pt->unknown_thread);
 err_free_queues:
 	intel_pt_log_disable();
 	auxtrace_queues__free(&pt->queues);