By default the new SDK will try to find all files automatically
by doing **\* inclusions. For our restore project we don't need
any of that so we turn it off.
See:
https://github.com/dotnet/sdk/blob/master/src/Tasks/Microsoft.NET.Build.Tasks/build/Microsoft.NET.Sdk.DefaultItems.props
for what it currently tries to find automatically.
This file is used in init-tools.cmd/sh, and replaces the "generated"
project file used previously. Because we are using MSBuild projects for
nuget restore now, we are able to "parameterize" the version of
Microsoft.DotNet.BuildTools based on an MSBuild property which is passed
in to the "dotnet restore" command in init-tools.
