##### SUMMARY
If a host has port set to a usermacro, the host is created successfully. On the next run, the update fails with `ValueError: invalid literal for int() with base 10: {$MACRO}`.

Tested with the latest `zabbix_host` from git.

##### ISSUE TYPE
- Bug Report

##### COMPONENT NAME
zabbix_host

##### ANSIBLE VERSION
latest

##### CONFIGURATION
Not relevant.

##### OS / ENVIRONMENT
Not relevant.

##### STEPS TO REPRODUCE
Have a host definition with usermacro used for port in an interface. Create the host via Ansible, then run the playbook again.

##### EXPECTED RESULTS
Success (reported as no change).

##### ACTUAL RESULTS

```paste below
Traceback (most recent call last):
  File \"/home/ansible/.ansible/tmp/ansible-tmp-1571042967.61-236562069605480/AnsiballZ_zabbix_host.py\", line 114, in <module>
    _ansiballz_main()
  File \"/home/ansible/.ansible/tmp/ansible-tmp-1571042967.61-236562069605480/AnsiballZ_zabbix_host.py\", line 106, in _ansiballz_main
    invoke_module(zipped_mod, temp_path, ANSIBALLZ_PARAMS)
  File \"/home/ansible/.ansible/tmp/ansible-tmp-1571042967.61-236562069605480/AnsiballZ_zabbix_host.py\", line 49, in invoke_module
    imp.load_module(__main__, mod, module, MOD_DESC)
  File \"/tmp/ansible_zabbix_host_payload_7ml4r2/__main__.py\", line 857, in <module>
  File \"/tmp/ansible_zabbix_host_payload_7ml4r2/__main__.py\", line 817, in main
  File \"/tmp/ansible_zabbix_host_payload_7ml4r2/__main__.py\", line 479, in check_all_properties
  File \"/tmp/ansible_zabbix_host_payload_7ml4r2/__main__.py\", line 437, in check_interface_properties
ValueError: invalid literal for int() with base 10: {$MACRO}
```

timeout=dict(type='int', default=10),
            interfaces=dict(type='list', required=False),
            force=dict(type='bool', default=True),
            proxy=dict(type='str', required=False),
            visible_name=dict(type='str', required=False),
            description=dict(type='str', required=False)
        ),
        supports_check_mode=True
    )
    if not HAS_ZABBIX_API:
        module.fail_json(msg=missing_required_lib('zabbix-api', url='https://pypi.org/project/zabbix-api/'), exception=ZBX_IMP_ERR)
    server_url = module.params['server_url']
    login_user = module.params['login_user']
    login_password = module.params['login_password']
    http_login_user = module.params['http_login_user']
    http_login_password = module.params['http_login_password']
    validate_certs = module.params['validate_certs']
    host_name = module.params['host_name']
    visible_name = module.params['visible_name']
    description = module.params['description']
    host_groups = module.params['host_groups']
    link_templates = module.params['link_templates']
    inventory_mode = module.params['inventory_mode']
    ipmi_authtype = module.params['ipmi_authtype']
    ipmi_privilege = module.params['ipmi_privilege']
    ipmi_username = module.params['ipmi_username']
    ipmi_password = module.params['ipmi_password']
    tls_connect = module.params['tls_connect']
    tls_accept = module.params['tls_accept']
    tls_psk_identity = module.params['tls_psk_identity']