Revert "Windows: Skip policy assembly for now"

This reverts commit a759e5091f.

The policy assembly is now skipped on XP from within the policy assembly
itself so it can be safely installed elsewhere.

packages/windows/installer/heimdal-installer.wxs

@@ -87,14 +87,8 @@
       <Merge Id='Heimdal.Assemblies.32' Language='0'
              SourceFile='$(var.InstDir32)\Heimdal.msm' />
 
-<!--
-   Until we have a work around for this bug on XP
-     http://sourceforge.net/p/wix/bugs/2034/
-   We need to punt on installing policy assemblies.
-
       <Merge Id='Heimdal.Policy.32' Language='0'
              SourceFile='$(var.InstDir32)\Heimdal.Policy.msm' />
--->
 
       <Merge Id='Runtime.32' Language='0'
              SourceFile='$(var.RuntimeModule32)' />
@@ -118,14 +112,8 @@
       <Merge Id='Heimdal.Assemblies.64' Language='0'
              SourceFile='$(var.InstDir64)\Heimdal.msm' />
 
-<!--
-   Until we have a work around for this bug on XP
-     http://sourceforge.net/p/wix/bugs/2034/
-   We need to punt on installing policy assemblies.
-
       <Merge Id='Heimdal.Policy.64' Language='0'
              SourceFile='$(var.InstDir64)\Heimdal.Policy.msm' />
--->
 
       <Merge Id='Runtime.64' Language='0'
              SourceFile='$(var.RuntimeModule64)' />
@@ -360,24 +348,14 @@
 
       <?ifdef Target64?>
       <MergeRef Id='Heimdal.Assemblies.64' />
+      <MergeRef Id='Heimdal.Policy.64' />
       <MergeRef Id='Runtime.64' />
       <?else?>
       <MergeRef Id='Heimdal.Assemblies.32' />
+      <MergeRef Id='Heimdal.Policy.32' />
       <MergeRef Id='Runtime.32' />
       <?endif?>
 
-<!--
-   Until we have a work around for this bug on XP
-     http://sourceforge.net/p/wix/bugs/2034/
-   We need to punt on installing policy assemblies.
-
-      <?ifdef Target64?>
-      <MergeRef Id='Heimdal.Policy.64' />
-      <?else?>
-      <MergeRef Id='Heimdal.Policy.32' />
-      <?endif?>
--->
-
       <?ifdef Target32?>
       <?ifdef Target64?>
       <!-- If we are building the combined installer, the 32-bit