R1:9acdd888930e

Diffusion commit feed: fix commit title repeated twice

Summary:
Before this change any commit in your web feed had a duplicated commit
title. Old example:

> FooBar committed REPOFOO 132abc: add documentation (authored by FooBar)
> add documentation

After this change the commit title "add documentation" is repeated only once.

| Before | After |
|---------------------|---------------------|
| {F313288,size=full} | {F313289,size=full} |

So the web feed is slimmer and less…