Add profiling outputs to .gitignore

"perf record" creates files perf.data/perf.data.old; these can be safely
ignored in .gitignore, to avoid showing up in git status.

ChangeLog:

2019-12-26  Christian Biesinger  <cbiesinger@google.com>

	* .gitignore: Add perf.data and perf.data.old.

Change-Id: I214ae9d6b7265c2cb1356f11c9b0b82e2b391352

.gitignore

@@ -41,6 +41,9 @@ TAGS.sub
 .gdbinit
 .gdb_history
 
+perf.data
+perf.data.old
+
 # ignore core files, but not java/net/protocol/core/
 core
 !core/

ChangeLog

@@ -1,3 +1,7 @@
+2019-12-26  Christian Biesinger  <cbiesinger@google.com>
+
+	* .gitignore: Add perf.data and perf.data.old.
+
 2019-10-17  Sergio Durigan Junior  <sergiodj@redhat.com>
 
 	* src-release.sh (GDB_SUPPORT_DIRS): Add libctf.