Fix the issue "unable to verify the first certificate in nodejs" when integrating Onlyoffice with Owncloud

ONLYOFFICE® is an online office suite integrated with a collaboration platform to manage documents, projects,team and customer relations in one place [ www.onlyoffice.com]. We have been using this product along with ownCloud® web application for several years and it provides an online platform to create/edit documents/slides/sheets stored in ownCloud environment.