##### 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}
```

inventory_mode:
        description:
            - Configure the inventory mode.
        choices: ['automatic', 'manual', 'disabled']
        version_added: '2.1'
    inventory_zabbix:
        description:
            - Add Facts for a zabbix inventory (e.g. Tag) (see example below).
            - Please review the interface documentation for more information on the supported properties
            - U(https://www.zabbix.com/documentation/3.2/manual/api/reference/host/object#host_inventory)
        version_added: '2.5'
    status:
        description:
            - Monitoring status of the host.
        choices: ['enabled', 'disabled']
        default: 'enabled'
    state:
        description:
            - State of the host.
            - On C(present), it will create if host does not exist or update the host if the associated data is different.
            - On C(absent) will remove a host if it exists.
        choices: ['present', 'absent']
        default: 'present'
    proxy:
        description:
            - The name of the Zabbix proxy to be used.
    interfaces:
        type: list
        description:
            - List of interfaces to be created for the host (see example below).