Ticket #48227 rpm.mk doesn't build srpms for 389-ds and nunc-stans
    
    https://fedorahosted.org/389/ticket/48227
    Reviewed by: nhosoi (Thanks!)
    Branch: 389-ds-base-1.3.4
    Fix Description: Add makefile macros for the nunc stans tarball name
    and url.  Grab the nunc stans tarball from the url with wget and
    copy it to the SOURCES.
    Platforms tested: Fedora 21
    Flag Day: no
    Doc impact: no
    
    (cherry picked from commit 684f8c5f10226ce4328a37c510a1ef0a61db4e69)