Build.cmd throws exception when you have a local nuget source

[rowanmiller]

Moving an issue that was reported in the EF repo - dotnet/efcore#272

Build.cmd throws exceptions and shows "NO Found" error when you have multiple source.

Steps to replicate ~

1. Add new package source (e.g. http://yourcoolmachine/feed.svc ) in nuget package manager in VS
2. Make sure you selected both "nuget.org" and your new fake source.
3. git clone entityframe in new folder.
4. Run commandline as an administrator and run build.cmd

You will see the error esp: "No Found"

Wordaround:

• uncheck your fake nuget source.

Let me know if you have problems in replicating the issue.

[glennc]

We added a flag for build to ignore failed sources: #591

I've created an issue in the universe repo to pass that flag in the Universe build. aspnet/Universe#112