Ticket #48048 - Fix coverity issues - 2015/3/1
    
    Coverity defect 13034 - Explicit null dereferenced (FORWARD_NULL)
    Description:  Added NULL check for operation and sdn.
    modified: update_pw_info in pw.c
    
    https://fedorahosted.org/389/ticket/48048
    
    Reviewed by rmeggins@redhat.com (Thank you, Rich!!)
    
    (cherry picked from commit f6eeaf93ff608e1381063155afa9acea6c3d8045)