I don't think this will happen in the near term, Sun where pushing Open Solaris quite heavily before this news, and I doubt that will change much. I'd say that Open Solaris has *lots* of potential and by simply giving it's best bits away doesn't make too much sense. I think Oracle will use Open Solaris to demonstrate that Oracle on a ZFS Open Solaris can be a very decent high end database server solution.
In a word no.
I did think it was a bit far fetched myself until I found out that Oracle were developing a ZFS competitor. http://en.wikipedia.org/wiki/Btrfs