provisioners/salt: #8991: Break if success

This commit ensures that we actually break when the download was
successful. Before it tried to download again for every iteration of the
loop. In addition the number of iterations have been increased. I've
experienced timeouts on third retry. Increasing to 5.

plugins/provisioners/salt/bootstrap-salt.ps1

@@ -60,8 +60,9 @@ Do {
     $retries++
     $ErrorActionPreference='Stop'
     $webclient.DownloadFile($url, $file)
+    break
  } catch [Exception] {
-    if($retries -eq 3) {
+    if($retries -eq 5) {
         $_
         $_.GetType()
         $_.Exception
@@ -73,7 +74,7 @@ Do {
     Start-Sleep -s 2
     }
 }
-Until($retries -eq 3)
+Until($retries -eq 5)
 
 
 # Install minion silently