chocolatey/chocolatey — pull request #534 by Gab-km (2014-08-01 11:33:32+00:00)
Title: Improve the condition whether NetWorkCredential is valid or not

This PR is new version of the PR #332 .

`[net.CredentialCache]::DefaultCredentials` may return a default `System.Net.NetworkCredential` instance.
But Chocolatey checks only if `$cred` is null or not for the need of NetworkCredential.
It may have another check whether this variable is the default NetworkCredential instance or not.