perf probe: Begin and end libdwfl report session correctly

Fix a trival bug about libdwfl usage of the report session, it should
explicitly begin and end a report session around dwfl_report_offline().
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/20150930164128.3733.59876.stgit@localhost.localdomainSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/probe-finder.c

@@ -70,6 +70,7 @@ static int debuginfo__init_offline_dwarf(struct debuginfo *dbg,
 	if (!dbg->dwfl)
 		goto error;
 
+	dwfl_report_begin(dbg->dwfl);
 	dbg->mod = dwfl_report_offline(dbg->dwfl, "", "", fd);
 	if (!dbg->mod)
 		goto error;
@@ -78,6 +79,8 @@ static int debuginfo__init_offline_dwarf(struct debuginfo *dbg,
 	if (!dbg->dbg)
 		goto error;
 
+	dwfl_report_end(dbg->dwfl, NULL, NULL);
+
 	return 0;
 error:
 	if (dbg->dwfl)