CA-142249: Prevent an ArgumentOutOfRangeException in ActionProgressDialog by ignoring negative values in the action's PercentComplete property.

Signed-off-by: Mihaela Stoica <mihaela.stoica@citrix.com>
Merge pull request #168 from MihaelaStoica/CA-142249

CA-142249: Prevent an ArgumentOutOfRangeException in ActionProgressDialo...