-Modify packimage excludelist search strategy to be amenable to rh directory.
-Update rhel plugin to do netboot in the manner that CentOS and Fedora are set to
git-svn-id: https://svn.code.sf.net/p/xcat/code/xcat-core/trunk@453 8638fb3e-16cb-4fca-ae20-7b5d299a9bcd