perf: Ignore perf.data.old

Tell git to ignore this file.

Signed-off-by: WANG Cong <amwang@redhat.com>
LKML-Reference: <20100125051052.3999.28082.sendpatchset@localhost.localdomain>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/tools/perf/.gitignore b/tools/perf/.gitignore
index fe08660..124760b 100644
--- a/tools/perf/.gitignore
+++ b/tools/perf/.gitignore
@@ -13,6 +13,7 @@
 perf*.html
 common-cmds.h
 perf.data
+perf.data.old
 tags
 TAGS
 cscope*