(chocolatey#612) Do not fail on failing repos

When a repository is failing, it should not cause everything to stop
working. The other configured repos should continue to provide results.
Update Nuget-Chocolatey (NuGet.Core.dll) with version that contains
a fix for issue
chocolatey/nuget-chocolatey#14.

Author: ferventcoder

lib/NuGet-Chocolatey/NuGet.Core.dll

@@ -160,8 +160,7 @@ public static IPackageRepository GetRemoteRepository(ChocolateyConfiguration con
                 configuration.Sources = updatedSources.Remove(updatedSources.Length - 1, 1).to_string();
             }
 
-            //todo well that didn't work on failing repos... grrr
-            var repository = new AggregateRepository(repositories)
+            var repository = new AggregateRepository(repositories, ignoreFailingRepositories: true)
             {
                 IgnoreFailingRepositories = true,
                 Logger = nugetLogger,