store: have the revlog determine which files are volatile itself This is a first step toward simplifying the walk step.

test-dirstate-version-fallback: future-proof the test for a different default Dirstate-v2 will become the default at some point, which would cause this test to fail. Let's save someone else the headache later.

clonebundles: add support for inline (streaming) clonebundles The idea behind inline clonebundles is to send them through the ssh or https connection to the Mercurial server. We've been using this specifically for streaming clonebundles, although it works for 'regular' clonebundles as well (but is less relevant, since pullbundles exist). We've had this enabled for around 9 months for a part of our users. A few benefits are: - no need to secure an external system, since everything goes through the same Mercurial server - easier scaling (in our case: no risk of inconsistencies between multiple mercurial-server mirrors and nginx clonebundles hosts) Remaining topics/questions right now: - The inline clonebundles don't work for https yet. This is because httppeer doesn't seem to support sending client capabilities. I didn't focus on that as my main goal was to get this working for ssh.