Fix patch since change to installer config in 8f20e89

Apologies, I broke this in https://github.com/theforeman/foreman-installer/commit/8f20e89c69bf2127ee6821abc9c5b1fde68e58e9 which fixed the use of kafo-export-params within the Rakefile/rpmbuild since kafo 0.3.6.

scratch builds: http://ci.theforeman.org/view/Packaging/job/packaging_build_deb_coreproject/308/