gitiles: remove unused var

Change-Id: I41c9760c2d6c504f517115002482ed49095acf7e

gitiles/client.go

diff --git a/gitiles/client.go b/gitiles/client.go
index 9ecf39b..e5c3872 100644
--- a/gitiles/client.go
+++ b/gitiles/client.go
@@ -44,7 +44,6 @@
 	addr    url.URL
 	client  http.Client
 	agent   string
-	jar     http.CookieJar
 	debug   bool
 }