Init the connection to the CouchDB server.

def init(self):
        """Init the connection to the CouchDB server."""
        if not self.export_enable:
            return None

        if self.user is None:
            server_uri = 'http://{}:{}/'.format(self.host,
                                                self.port)
        else:
            server_uri = 'http://{}:{}@{}:{}/'.format(self.user,
                                                      self.password,
                                                      self.host,
                                                      self.port)

        try:
            s = couchdb.Server(server_uri)
        except Exception as e:
            logger.critical("Cannot connect to CouchDB server %s (%s)" % (server_uri, e))
            sys.exit(2)
        else:
            logger.info("Connected to the CouchDB server %s" % server_uri)

        try:
            s[self.db]
        except Exception as e:
            # Database did not exist
            # Create it...
            s.create(self.db)
        else:
            logger.info("There is already a %s database" % self.db)

        return s