CCBC-274 Handle getl/unl when purging the server

Thanks Robert Groenenberg

Change-Id: I4155d811314d22b513f42b50d9ce0b731353e7c1
Reviewed-on: http://review.couchbase.org/29344
Tested-by: Sergey Avseyev <sergey.avseyev@gmail.com>
Reviewed-by: Mark Nunberg <mnunberg@haskalah.org>