Don't clear the exit code from the Finally block

It turns out that the Finally block does not see the exit code from the
`exit` call that triggered it, but from an earlier state. And it seems
that actions take in the Finally block other than `exit` will not affect
the $LastErrorCode set by the `exit` that triggered the Finally block.

Signed-off-by: Paul "TBBle" Hampson <Paul.Hampson@Pobox.com>

hack/ci/windows.ps1

@@ -1012,9 +1012,6 @@ Catch [Exception] {
     Throw $_
 }
 Finally {
-    # Preserve the LastExitCode of the tests
-    $tmpLastExitCode = $LastExitCode
-
     $ErrorActionPreference="SilentlyContinue"
     $global:ProgressPreference=$origProgressPreference
     Write-Host  -ForegroundColor Green "INFO: Tidying up at end of run"
@@ -1053,6 +1050,4 @@ Finally {
 
     $Dur=New-TimeSpan -Start $StartTime -End $(Get-Date)
     Write-Host -ForegroundColor $FinallyColour "`nINFO: executeCI.ps1 exiting at $(date). Duration $dur`n"
-
-    exit $tmpLastExitCode
 }