Merge pull request #394 from kazegusuri/fix_reauth

fix recursive reauth failure
diff --git a/openstack/client.go b/openstack/client.go
index 6818d9d..aaf940b 100644
--- a/openstack/client.go
+++ b/openstack/client.go
@@ -109,6 +109,7 @@
 
 	if options.AllowReauth {
 		client.ReauthFunc = func() error {
+			client.TokenID = ""
 			return AuthenticateV2(client, options)
 		}
 	}