Bug Description: We were previous checking if an unsigfned int was less than zero

Fix Description:  Improve config validation by using long instead of PRUint64

https://fedorahosted.org/389/ticket/48636

Reviewed by: nhosoi(Thanks!)

(cherry picked from commit 43d5ac680f7781f95205db94e5ff2958d39b78a4)
(cherry picked from commit b8239e0da865f33cae930088dd2a746a49f2d32a)