Ticket 477779 - Need to lock server list when removing list
Description: Need to hold the write lock when deleting the server list.
There is no need to lock the list in the close function,
as all active threads should be stopped. In 1.3.3, the
dynamic plugin feature will also safely handle the plugin
shutdown.
https://fedorahosted.org/389/ticket/47779
Reviewed by: tbordaz(Thanks!)