Bug 711906 - ns-slapd segfaults using suffix referrals
    
    https://bugzilla.redhat.com/show_bug.cgi?id=711906
    Resolves: bug 711906
    Bug Description: ns-slapd segfaults using suffix referrals
    Reviewed by: nkinder (Thanks!)
    Branch: RHEL-6
    Fix Description: Check node->mtn_be for NULL before dereferencing it
    Platforms tested: RHEL6 x86_64
    Flag Day: no
    Doc impact: no
    (cherry picked from commit fb9b444fc620a9ccae03d578c7c4b8ed56b82465)