perf ui: Add ui_progress__finish()

Sometimes we need to know when the progress bar should disappear.

Checking curr >= total wasn't enough since there're cases not met that
condition for the last call.

So add a new ->finish callback to identify this explicitly.  Currently
only GTK frontend needs it.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1352813436-14173-4-git-send-email-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/session.c

@@ -1458,6 +1458,7 @@ more:
 	session->ordered_samples.next_flush = ULLONG_MAX;
 	err = flush_sample_queue(session, tool);
 out_err:
+	ui_progress__finish();
 	perf_session__warn_about_errors(session, tool);
 	perf_session_free_sample_buffers(session);
 	return err;