That I don't know. Here is what the openSUSE people told use about one of the vega strike files.
OpenSUSE's legal team found out a weird license tag in our Sol system file. It turns out the guy who contributed it did so under a noncommercial license. Many people don't know this, but noncommercial licenses aren't compatible with the GPL, and we want our data to be GPL... *snip*
...I'd like to point out, that this is a rather important matter. Without a clear license situation (ie: all data being GPL or some other FOSS license), the game won't get into Factory (ie: it won't be part of openSUSE). I'd expect Fedora to have the same concerns, they must just have missed the file.
You may want to check and see if CC-BY-SA is compatible with the GPL. As stated though, it would only mean that anything released as non-commercial would just have to be a separate download rather than bundled in with the package from a particular distro. If you can live with it, CC-BY-SA 3.0 would probably be the best way to go. That choice though, is up to you.