roles: server doesn't change server address after reload

[themilchenko]

Now http role can't change address or port of http server while instance running (with config:reload(), for example).

Reproducer

There is a config with httpd role:

app:
  file: 'init.lua'

groups:
  group001:
    replicasets:
      replicaset001:
        instances:
          instance001:
            roles: [roles.httpd]
            roles_cfg:
              roles.httpd:
                default:
                  listen: '127.0.0.1:8080'
            iproto:
              listen:
              - uri: '127.0.0.1:3301'

Let's start instance:

$ tt start app

Now I want to change a port of default server:

<                   listen: '127.0.0.1:8080'
---
>                   listen: '127.0.0.1:8081'

And apply config with config:reload() command on running instance:

$ tt connect app
app> require('config'):reload()

And check if port was changed:

$ lsof -i :8080 
COMMAND      PID      USER FD   TYPE  DEVICE SIZE/OFF NODE NAME
tarantool 221085 milchenko 25u  IPv4 1361754      0t0  TCP localhost:http-alt (LISTEN)
$ lsof -i :8081

And it's not. Need to fix changing a port of address without restarting an instnace.