[merge] remove static BzrDir.create_repository

[John Arbash Meinel]

John Arbash Meinel has voted approve.
Status is now: Approved
Comment:
Yeah, I found that very difficult, too. I thought I remember another 
function that worked like that. Which was static on the base class, but 
instanced per child class. But it might have been static on BzrDir, and 
instanced on all of the BzrDirFormats, or somesuch.

Anyway, I'm happy to see this cleaned up.

For details, see: 
http://bundlebuggy.aaronbentley.com/request/%3Ce01316480708160317o374a023ar3e0fd5d3e1755456%40mail.gmail.com%3E