Avoid redirect

Hey guys

This pull request tries to avoid an unnecessary request to home#show that will redirect again to stream#index.

Here is the commit that introduced this change: 
https://github.com/diaspora/diaspora/commit/bbd4ee

In the past it was done in this way because home#show action based on conditions would redirect to one way or other, but with the code as it stands right now this won't happen.

What do you think?