Switch to registry based verification (#252)

* Switch to registry based verification

Except for Server 2008 which doesn't use registry to store status, this will resolve issues with attempting to activate windows when English is not the system display language.

* Consolidate to a single guaranteed return

More optimal given a single guaranteed return

* Update catch behavior for failed license lookup

Log the message rather than set $active which is already false

sysprep/activate_instance.ps1

@@ -266,17 +266,33 @@ function Verify-ActivationStatus {
   [String]$activation_status = $null
   [String]$status = $null
 
-  try {
-    $slmgr_status = & cscript //E:VBScript //nologo $env:windir\system32\slmgr.vbs /dli
-  }
-  catch {
-    return $active
+  # Server 2008 doesn't store activation status in registry; check slmgr
+  if([Environment]::OSVersion.Version.Major -eq 6 -and [Environment]::OSVersion.Version.Minor -le 1)
+  {
+    try {
+      $slmgr_status = & cscript //E:VBScript //nologo $env:windir\system32\slmgr.vbs /dli
+    }
+    catch {
+      Write-Host "Error getting slmgr license status output."
+    }
+    $status = $slmgr_status | Select-String -Pattern '^License Status:'
+    # The initial space is to ensure "Unlicensed" does not match.
+    if ($status -match ' Licensed') {
+      $active = $true
+    }
   }
-
-  $status = $slmgr_status | Select-String -Pattern '^License Status:'
-  # The initial space is to ensure "Unlicensed" does not match.
-  if ($status -match ' Licensed') {
-    $active = $true
+  # All server versions newer than 2008
+  else {
+    try {
+      $activation_status = (Get-ItemProperty -Path "HKLM:\SOFTWARE\Microsoft\Windows NT\CurrentVersion\SoftwareProtectionPlatform\Activation" -Name ProductActivationResult).ProductActivationResult
+    }
+    catch {
+      Write-Host "Error retrieving last activation result registry key."
+    }
+    # Anything other than 0x0 is a failure.
+    if ($activation_status -eq '0') {
+      $active = $true
+    }
   }
   return $active
 }