Fix JWT token not considered valid created by signup
Fix JWT token not considered valid created by signup

refs #94

rickmak/skygear-server,SkygearIO/skygear-server,rickmak/skygear-server,SkygearIO/skygear-server,rickmak/skygear-server,SkygearIO/skygear-server,SkygearIO/skygear-server