Disable package harvesting for the vertical build packages

Microsoft.NETCore.Platforms and Microsoft.NETCore.Targets don't
need to harvest anything so disabing stable package harvesting
for them so we don't need to restore all the old stable packages
for the vertical builds.

Author: weshaggard

pkg/Microsoft.NETCore.Platforms/Microsoft.NETCore.Platforms.pkgproj

@@ -1,12 +1,14 @@
 <?xml version="1.0" encoding="utf-8"?>
 <Project ToolsVersion="14.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
   <Import Project="$([MSBuild]::GetDirectoryNameOfFileAbove($(MSBuildThisFileDirectory), dir.props))\dir.props" />
-  
+
   <PropertyGroup>
     <PackageVersion>$(PlatformPackageVersion)</PackageVersion>
     <SkipValidatePackage>true</SkipValidatePackage>
+    <!-- We don't need to harvest the stable packages to build this -->
+    <HarvestStablePackage>false</HarvestStablePackage>
   </PropertyGroup>
-  
+
   <ItemGroup>
     <File Include="runtime.json" />
     <!-- make this package installable and noop in a packages.config-based project -->

pkg/Microsoft.NETCore.Targets/Microsoft.NETCore.Targets.pkgproj

@@ -1,10 +1,12 @@
 <?xml version="1.0" encoding="utf-8"?>
 <Project ToolsVersion="14.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
   <Import Project="$([MSBuild]::GetDirectoryNameOfFileAbove($(MSBuildThisFileDirectory), dir.props))\dir.props" />
-  
+
   <PropertyGroup>
     <PackageVersion>2.0.0</PackageVersion>
     <SkipValidatePackage>true</SkipValidatePackage>
+    <!-- We don't need to harvest the stable packages to build this -->
+    <HarvestStablePackage>false</HarvestStablePackage>
   </PropertyGroup>
 
   <ItemGroup>