Bump livecd-tools release to el7

- Make was creating an el7 src rpm and then looking for el6.
Make CONFIG_REPOS point to /opt/ for rhel7 packages
Bump pungi version

- Anaconda has dropped anaconda-runtime scripts and moved to Lorax
- pungi 2.0.22 still uses anaconda-runtime buildinstall, so we need to bump the
package to one that supports Lorax
- Use the default pungi binary (/usr/bin/pungi) and drop the patches in our tree
- Document a backup necessary for compatibility with Lorax in support/backup/
Replace clip-rhel6 with clip-rhel7 in the bootstrap