Fixed issue with WebGitNet directory detection / creation

When a non-existing path was specified in the URL, it would be created in the process of testing for / creating a info/WebGitNet path under it. Fixed to only create when the path exists and is known to be a repo. For example, browsing to:

```Text
http://localhost/Content/XXX
```

would cause a folder structure XXX/info/WebGitNet to be created under the base repository folder. This was occurring in GitUtilities.RepoInfoPath

Also, simplified and encapsulated the testing for if a folder is a repo and testing to see if the repo is bare.