Do not store Spawner.ip/port on spawner.server

This was part of an attempt to get the url from self.server.bind_url that didn't end up getting used

shouldn't mutate db state when getting the environment

jupyterhub/spawner.py

@@ -873,9 +873,6 @@ class Spawner(LoggingConfigurable):
 
         if self.server:
             base_url = self.server.base_url
-            if self.ip or self.port:
-                self.server.ip = self.ip
-                self.server.port = self.port
             env['JUPYTERHUB_SERVICE_PREFIX'] = self.server.base_url
         else:
             # this should only occur in mock/testing scenarios