perf trace: Call machine__exit() at exit

Otherwise 'perf trace' leaves a temporary file /tmp/perf-vdso.so-XXXXXX.

  $ perf trace -o log true
  $ ls -l /tmp/perf-vdso.*
  -rw------- 1 root root 8192 Nov  8 03:08 /tmp/perf-vdso.so-5bCpD0

Signed-off-by: Andrei Vagin <avagin@openvz.org>
Reviewed-by: Jiri Olsa <jolsa@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Vasily Averin <vvs@virtuozzo.com>
Link: http://lkml.kernel.org/r/20171108002246.8924-1-avagin@openvz.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/builtin-trace.c

@@ -1138,6 +1138,14 @@ static int trace__symbols_init(struct trace *trace, struct perf_evlist *evlist)
 	return err;
 }
 
+static void trace__symbols__exit(struct trace *trace)
+{
+	machine__exit(trace->host);
+	trace->host = NULL;
+
+	symbol__exit();
+}
+
 static int syscall__alloc_arg_fmts(struct syscall *sc, int nr_args)
 {
 	int idx;
@@ -2481,6 +2489,8 @@ out_disable:
 	}
 
 out_delete_evlist:
+	trace__symbols__exit(trace);
+
 	perf_evlist__delete(evlist);
 	trace->evlist = NULL;
 	trace->live = false;