BZ #1033249 - enable new variable to be overridden.

https://bugzilla.redhat.com/show_bug.cgi?id=1033249

This makes all variables in our hostgroups have their override set to true.
If there is a value specified in seeds, that is set as well.
Merge pull request #62 from jguiditta/set_overrides

BZ #1033249 - enable new variable to be overridden.