add memcache as godep

Godeps/Godeps.json

@@ -155,6 +155,11 @@
 			"ImportPath": "gopkg.in/redis.v2",
 			"Comment": "v2.3.2",
 			"Rev": "e6179049628164864e6e84e973cfb56335748dea"
-		}
+		},
+    {
+      "ImportPath": "github.com/bradfitz/gomemcache/memcache",
+      "Comment": "release.r60-40-g72a6864",
+      "Rev": "72a68649ba712ee7c4b5b4a943a626bcd7d90eb8"
+    }
 	]
 }