Ticket 48858 - Segfault changing nsslapd-rootpw
Bug Description: py.ldap has a bug where it will send empty change lists. This
trigged a segfault in Directory Server where hash_rootpw expected there to be
at least a single value to act upon
Fix Description: Check that mod_bvalues is not NULL
https://fedorahosted.org/389/ticket/48858
Author: wibrown
Review by: nhosoi (Thank you!)