Saving Culture and Hostnames, results in multiple domain .config files.

[KevinJump]

Updating and Saving the culture and hostnames settings for a site results in uSync creating new config files in the domain folder.

because of the way we check for the guid and the guid isn't a reliable thing for domains we end up with multiple versions of the config.

the check for file clashes needs to be updated.

[KevinJump]

fixed in #8d7fd7122468c7885a6db470f915027cb927c459