Pin 17.10.0-ee-preview-3 for insider

scripts/docker/docker-pull.ps1

@@ -11,7 +11,7 @@ function DockerPull {
   }
 
   Write-Host Installing $image ...
-  $j = Start-Job -ScriptBlock { docker pull $args[0] } -ArgumentList $image
+  $j = Start-Job -ScriptBlock { docker pull $args[0] } -ArgumentList "$image"
   while ( $j.JobStateInfo.state -ne "Completed" -And $j.JobStateInfo.state -ne "Failed" ) {
     Write-Host $j.JobStateInfo.state
     Start-Sleep 30

windows_server_insider_docker.json

@@ -148,7 +148,7 @@
     "disk_type_id": "1",
     "docker_images": "microsoft/windowsservercore-insider microsoft/nanoserver-insider",
     "docker_provider": "DockerProvider",
-    "docker_version": "preview",
+    "docker_version": "17.10.0-ee-preview-3",
     "headless": "false",
     "iso_checksum": "135b2cd050b55de7076fa50f2e35e816a7def180413d54c0681590cc80d18798",
     "iso_checksum_type": "sha256",