Ticket #47772 empty modify returns LDAP_INVALID_DN_SYNTAX
https://fedorahosted.org/389/ticket/47772
Reviewed by: tbordaz, mreynolds (Thanks!)
Branch: 389-ds-base-1.3.2
Fix Description: tbordaz pointed out a couple of other places where the
pblock modify_mods structure is being referenced directly, and needs to be
checked for NULL.
Platforms tested: RHEL6 x86_64
Flag Day: no
Doc impact: no