##### 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}
```

module = AnsibleModule(
        argument_spec=dict(
            server_url=dict(type='str', required=True, aliases=['url']),
            login_user=dict(type='str', required=True),
            login_password=dict(type='str', required=True, no_log=True),
            host_name=dict(type='str', required=True),
            http_login_user=dict(type='str', required=False, default=None),
            http_login_password=dict(type='str', required=False, default=None, no_log=True),
            validate_certs=dict(type='bool', required=False, default=True),
            host_groups=dict(type='list', required=False),
            link_templates=dict(type='list', required=False),
            status=dict(default="enabled", choices=['enabled', 'disabled']),
            state=dict(default="present", choices=['present', 'absent']),
            inventory_mode=dict(required=False, choices=['automatic', 'manual', 'disabled']),
            ipmi_authtype=dict(type='int', default=None),
            ipmi_privilege=dict(type='int', default=None),
            ipmi_username=dict(type='str', required=False, default=None),
            ipmi_password=dict(type='str', required=False, default=None, no_log=True),
            tls_connect=dict(type='int', default=1),
            tls_accept=dict(type='int', default=1),
            tls_psk_identity=dict(type='str', required=False),
            tls_psk=dict(type='str', required=False),
            ca_cert=dict(type='str', required=False, aliases=['tls_issuer']),
            tls_subject=dict(type='str', required=False),
            inventory_zabbix=dict(required=False, type='dict'),