Introduced spec to make sure specified manifest takes precedence over standard header.
Introduced spec to make sure specified manifest takes precedence over standard header.

git-svn-id: f481de8ecb0d1e2ade8c586a5c716a32a1f3e8c1@711978 13f79535-47bb-0310-9956-ffa450edef68

liamchristopher/buildr,apache/buildr,stewi2/buildr,mariusk/buildr-kawa,jpcaruana/buildr,atoulme/buildr,liamchristopher/buildr,ittayd/buildr,atoulme/buildr,assaf/buildr,liamchristopher/buildr,jpcaruana/buildr,stewi2/buildr,ittayd/buildr,liamchristopher/buildr,stewi2/buildr,atoulme/buildr,apache/buildr,assaf/buildr,stewi2/buildr,apache/buildr,mariusk/buildr-kawa,jpcaruana/buildr,apache/buildr,mariusk/buildr-kawa,assaf/buildr,jpcaruana/buildr,ittayd/buildr