They're pretty much unrelated. Savana doesn't aim to provide all of the functionality of git. What it DOES do is make it really easy to work "the right way" with SVN, with "the right way" defined as:
1. Every time I'm going to code a new feature/bug fix, I do it in a private branch.
2. I checkin normally on this branch.
3. When I'm ready to promote my changes, I first sync down any more recent changes from the trunk.
4. Optionally, I can have someone else look at my branch to do a code read.
5. I promote (merge my changes back to trunk) and drop my private branch.
It's currently possible to work like this now with subversion, but it's pretty ugly and a pain requiring long commands, and developers generally don't like it because it is such a pain to set up the private branches and merge them, so they end up just doing everything in trunk. Savana is essentially just syntactic sugar on top of (potentially multiple) underlying uglier svn commands. Savana aims to make it easy to set up and merge private branches, lowering developer resistance to using them.