React to aspnet/Universe#290 fix

- pick up latest `build.cmd` file
  - preserve lack of Core CLR DNX when building this repo
- correct case of `Nuget.config` filename for consistency

build.cmd

@@ -2,12 +2,15 @@
 cd %~dp0
 
 SETLOCAL
-SET CACHED_NUGET=%LocalAppData%\NuGet\NuGet.exe
+SET NUGET_VERSION=latest
+SET CACHED_NUGET=%LocalAppData%\NuGet\nuget.%NUGET_VERSION%.exe
+SET BUILDCMD_KOREBUILD_VERSION=""
+SET BUILDCMD_DNX_VERSION=""
 
 IF EXIST %CACHED_NUGET% goto copynuget
 echo Downloading latest version of NuGet.exe...
 IF NOT EXIST %LocalAppData%\NuGet md %LocalAppData%\NuGet
-@powershell -NoProfile -ExecutionPolicy unrestricted -Command "$ProgressPreference = 'SilentlyContinue'; Invoke-WebRequest 'https://www.nuget.org/nuget.exe' -OutFile '%CACHED_NUGET%'"
+@powershell -NoProfile -ExecutionPolicy unrestricted -Command "$ProgressPreference = 'SilentlyContinue'; Invoke-WebRequest 'https://dist.nuget.org/win-x86-commandline/%NUGET_VERSION%/nuget.exe' -OutFile '%CACHED_NUGET%'"
 
 :copynuget
 IF EXIST .nuget\nuget.exe goto restore
@@ -15,14 +18,23 @@ md .nuget
 copy %CACHED_NUGET% .nuget\nuget.exe > nul
 
 :restore
-IF EXIST packages\KoreBuild goto run
-.nuget\NuGet.exe install KoreBuild -ExcludeVersion -o packages -nocache -pre
+IF EXIST packages\Sake goto getdnx
+IF %BUILDCMD_KOREBUILD_VERSION%=="" (
+    .nuget\nuget.exe install KoreBuild -ExcludeVersion -o packages -nocache -pre
+) ELSE (
+    .nuget\nuget.exe install KoreBuild -version %BUILDCMD_KOREBUILD_VERSION% -ExcludeVersion -o packages -nocache -pre
+)
 .nuget\NuGet.exe restore
 .nuget\NuGet.exe install Sake -ExcludeVersion -Source https://www.nuget.org/api/v2/ -Out packages
 
-IF "%SKIP_DNX_INSTALL%"=="1" goto run
-CALL packages\KoreBuild\build\dnvm upgrade -runtime CLR -arch x86
+:getdnx
+IF "%SKIP_DNX_INSTALL%"=="" (
+    IF "%BUILDCMD_DNX_VERSION%"=="" (
+        BUILDCMD_DNX_VERSION=latest
+    )
+    CALL packages\KoreBuild\build\dnvm install %BUILDCMD_DNX_VERSION% -runtime CLR -arch x86 -alias default
+) ELSE (
+    CALL packages\KoreBuild\build\dnvm use default -runtime CLR -arch x86
+)
 
-:run
-CALL packages\KoreBuild\build\dnvm use default -runtime CLR -arch x86
 packages\Sake\tools\Sake.exe -I packages\KoreBuild\build -f makefile.shade %*