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

Change-Id: I7bbf0afab2d0804e5026ff3d0dfa26f686a7c8d6
MultiPart: 16/28
PresubmitTest: none
diff --git a/.gitignore b/.gitignore
index 5f037ee..d6acd0d 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,3 +1,5 @@
+/.jiri
+#TODO(nlacasse): Get rid of .v23 below once v23->jiri transition is complete.
 # Build artifacts
 /bin
 /creds