Fix typo

Author: micafer

libcloud/compute/drivers/openstack.py

@@ -4309,7 +4309,7 @@ def ex_attach_floating_ip_to_node(self, node, ip, port_id=None):
         :type       ip: ``str`` or :class:`OpenStack_1_1_FloatingIpAddress`
 
         :param      port_id: Optional node port ID to attach the floating IP
-        :type       ip: ``str``
+        :type       port_id: ``str``
 
         :rtype: ``bool``
         """