Update Signing.props

Author: wtgodbe

eng/Signing.props

@@ -96,9 +96,9 @@
     </_InstallersToPublish>
 
     <Artifact Include="@(_InstallersToPublish)" Kind="Blob">
-      <!-- Working around msbuild not being able to negate the result of Contains() outside of targets -->
-      <IsShipping Condition="$([System.String]::Copy('%(RecursiveDir)').StartsWith('Shipping')) != 'true'">false</IsShipping>
-      <IsShipping Condition="$([System.String]::Copy('%(RecursiveDir)').StartsWith('Shipping')) == 'true'">true</IsShipping>
+      <IsShipping>true</IsShipping>
+      <IsShipping Condition="$([System.String]::Copy('%(RecursiveDir)').StartsWith('NonShipping'))">false</IsShipping>
+      <IsShipping Condition="$([System.String]::Copy('%(Filename)').ToLowerInvariant().Contains('wixpack.zip'))">false</IsShipping>
     </Artifact>
   </ItemGroup>