https://fedorahosted.org/389/ticket/47384

https://fedorahosted.org/389/attachment/ticket/47384/0001-Ticket-47384-Plugin-library-path-validation.3.patch

Description: commit a4b81c0ae59a4246d2d44790efea093a62fc972c
only checks the invalid plugin path when the value is modified.
This patch adds the check when a plugin entry is added.