Bug 750625 - Fix Coverity (11064) Dereference before null check
    
    https://bugzilla.redhat.com/show_bug.cgi?id=750625
    
    slapd/pw_retry.c (get_entry)
    
    Bug Description: Dereferencing pointer "pb" before a null check.
    
    Fix Description: Check if "pb" is NULL or not first.  If NULL,
    goto bail.