Keep $(Out) property default where it can be shared among targets

This property was improperly moved to build.proj, therefore causing the
projects to stop having a default value for it, and causing F5 scenarios
to break for the VS extension authoring, which needs to package the .nupkg
from the $(Out) directory for deployment to the experimental instance.

This did work fine for CI builds, since the Out property is explicitly
passed down when building solutions and projects.

Author: kzu

build.proj

@@ -13,7 +13,6 @@
 	<PropertyGroup>
 		<NuGetUrl Condition=" '$(NuGetUrl)' == '' ">https://dist.nuget.org/win-x86-commandline/v3.4.4/NuGet.exe</NuGetUrl>
 		<RestorePackages>false</RestorePackages>
-		<Out Condition=" '$(Out)' == '' ">$(MSBuildThisFileDirectory)out</Out>
 		<RunCodeAnalysis Condition=" '$(RunCodeAnalysis)' == ''">false</RunCodeAnalysis>
 		<IntermediateOutputPath>.nuget\</IntermediateOutputPath>
 		<PackagesPath>$(IntermediateOutputPath)packages</PackagesPath>

build.props

@@ -16,4 +16,9 @@
 		<Message Importance="high" Text="$(VsInstallRoot)" />
 	</Target>
 
+	<PropertyGroup>
+		<!-- Keep this property here, since this .props file is also imported from the Shared.props file -->
+		<Out Condition=" '$(Out)' == '' ">$(MSBuildThisFileDirectory)out</Out>
+	</PropertyGroup>
+
 </Project>