Stop using a global cache for yarn - build fails on Jenkins

Change-Id: Id39fc94315b70c927f87e281101ab761d6444f10
diff --git a/WORKSPACE b/WORKSPACE
index f461013..cb72012 100644
--- a/WORKSPACE
+++ b/WORKSPACE
@@ -172,6 +172,7 @@
 yarn_install(
     name = "npm",
     package_json = "//web/gui2:package.json",
+    use_global_yarn_cache = False,
     yarn_lock = "//web/gui2:yarn.lock",
 )