appveyor uses the latest nuget

appveyor.yml

@@ -4,9 +4,6 @@ nuget:
 init:
   - git config --global core.autocrlf true
   
-install:
- - cmd: nuget sources add -Name api.nuget.org -Source https://api.nuget.org/v3/index.json
-
 before_build:
  - ps: "&{$Branch='dev';iex ((new-object net.webclient).DownloadString('https://raw.githubusercontent.com/aspnet/Home/dev/dnvminstall.ps1'))}"
  - ps: dnvm upgrade
@@ -18,6 +15,4 @@ before_build:
  - ps: npm install -g gulp bower
  - ps: dnu restore
 # Use NuGet 2.*
- - ps: (New-Object Net.WebClient).DownloadFile('https://www.nuget.org/nuget.exe', 'C:\Tools\NuGet\NuGet.exe')
- - ps: nuget restore
  - cmd: set PATH=C:\Program Files (x86)\MSBuild\14.0\Bin;%PATH%