TBR: travel: Add '/.jiri' to .gitignore in all repos.

Change-Id: I16915c48a2ce58c3c149700c2e9326e612607058
MultiPart: 26/28
PresubmitTest: none
diff --git a/.gitignore b/.gitignore
index 68dbe6f..e5a20c4 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,3 +1,5 @@
+/.jiri
+#TODO(nlacasse): Get rid of .v23 below once v23->jiri transition is complete.
 /.v23
 /ifc
 /node_modules