Fix provisioning disable defragmentation for windows

If no scheduled task exist it would throw error causing
provisioning to fail. Now catch when scheduling does not exist.

Task-number: QTQAINFRA-2823
Change-Id: I3bf24df6116b6c978171950bf5bf954f5ddee533
Reviewed-by: Tony Sarajärvi <tony.sarajarvi@qt.io>

coin/provisioning/common/windows/disable-defragment.ps1

@@ -1,6 +1,6 @@
 #############################################################################
 ##
-## Copyright (C) 2018 The Qt Company Ltd.
+## Copyright (C) 2019 The Qt Company Ltd.
 ## Contact: http://www.qt.io/licensing/
 ##
 ## This file is part of the provisioning scripts of the Qt Toolkit.
@@ -31,4 +31,42 @@
 ##
 #############################################################################
 
-schtasks /Delete /TN "\Microsoft\Windows\Defrag\ScheduledDefrag" /F
+# Windows 7 does not have Get-ScheduledTask and Unregister-ScheduledTask
+# thus needing its own version.
+Write-Host "Disabling defragmentation"
+$version = Get-CimInstance Win32_OperatingSystem | Select-Object -ExpandProperty Caption
+if ($version -like '*Windows 7*'){
+    $pi = New-Object System.Diagnostics.ProcessStartInfo
+    $pi.FileName = "C:\Windows\System32\schtasks.exe"
+    $pi.RedirectStandardError = $true
+    $pi.UseShellExecute  = $false
+    $pi.Arguments = "/Delete /TN `"\Microsoft\Windows\Defrag\ScheduledDefrag`" /F"
+    $prog = New-Object System.Diagnostics.Process
+    $prog.StartInfo = $pi
+    $prog.Start() | Out-Null
+    $err = $prog.StandardError.ReadToEnd()
+    $prog.WaitForExit()
+    if ($prog.ExitCode -eq 0){
+        Write-Host "Scheduled defragmentation removed"
+    } else {
+        if ($err -like '*cannot find the file*'){
+            Write-Host "No scheduled defragmentation task found"
+            exit 0
+        } else {
+            Write-Host "Error while deleting scheduled defragmentation task: $err"
+        }
+    }
+}
+else {
+    try {
+        $state = (Get-ScheduledTask -ErrorAction Stop -TaskName "ScheduledDefrag").State
+        Write-Host "Scheduled defragmentation task found in state: $state"
+    }
+    catch {
+        Write-Host "No scheduled defragmentation task found"
+        exit 0
+    }
+    Write-Host "Unregistering scheduled defragmentation task"
+    Unregister-ScheduledTask -ErrorAction Stop -Confirm:$false -TaskName ScheduledDefrag
+    Write-Host "Scheduled Defragmentation task was cancelled"
+}