check error in initializing remote store

Signed-off-by: David Lawrence <david.lawrence@docker.com> (github: endophage)

client/client.go

@@ -173,6 +173,9 @@ func (r *NotaryRepository) Initialize(uCryptoService *cryptoservice.UnlockedCryp
 
 	// All the timestamp keys are generated by the remote server.
 	remote, err := getRemoteStore(r.baseURL, r.gun, r.roundTrip)
+	if err != nil {
+		return err
+	}
 	rawTSKey, err := remote.GetKey("timestamp")
 	if err != nil {
 		return err