##### 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}
```

for interface in interfaces:
            if 'type' not in interface:
                module.fail_json(msg="(interface) type needs to be specified for interface '%s'." % interface)
            interfacetypes = {'agent': 1, 'snmp': 2, 'ipmi': 3, 'jmx': 4}
            if interface['type'] in interfacetypes.keys():
                interface['type'] = interfacetypes[interface['type']]
            if interface['type'] < 1 or interface['type'] > 4:
                module.fail_json(msg="Interface type can only be 1-4 for interface '%s'." % interface)
            if 'useip' not in interface:
                interface['useip'] = 0
            if 'dns' not in interface:
                if interface['useip'] == 0:
                    module.fail_json(msg="dns needs to be set if useip is 0 on interface '%s'." % interface)
                interface['dns'] = ''
            if 'ip' not in interface:
                if interface['useip'] == 1:
                    module.fail_json(msg="ip needs to be set if useip is 1 on interface '%s'." % interface)
                interface['ip'] = ''
            if 'main' not in interface:
                interface['main'] = 0
            if 'port' not in interface:
                if interface['type'] == 1:
                    interface['port'] = "10050"
                elif interface['type'] == 2:
                    interface['port'] = "161"
                elif interface['type'] == 3:
                    interface['port'] = "623"
                elif interface['type'] == 4:
                    interface['port'] = "12345"
            if interface['type'] == 1: