Unable to specify hostname in logging endpoint

[ejthurgo]

Unable to specify hostname in logging endpoint

Overview

1. OS name and version.
OSX darwin/amd64
2. go version output
go 1.9.2
3. waflyctl --version in recent releases or brew info waflyctl output.
master branch
4. Description of the problem. What is happening that shouldn't?
Specifying a hostname in the address field in the logging configuration causes the API to error.
Currently the Address defined in the TOML conffig is used for both Address and IPV4 fields in the API. Validation on the IPV4 value prevents this from being a hostname.
5. Description of the expected behaviour.
The Address can be either hostname, IPv4 or IPv6 address and is automatically parsed by the API. We should just not populate the IPv4 attribute when sending through to the API and allow the API to automatically parse the address field.
6. Exact steps to reproduce the error.
Use a hostname in the address field.