changelog-v2: add a configuration to disable rank computation We encountered a graph where rank computation was pathologically slow. We add an option to disable this computation while this is getting fixed. Disabling the rank computation should allow for testing other changelog-v2 features undisturbed (like changeset-based copy tracing). I am purposely not adding a test for the new non-default code path, as this is a temporary work around of an experimental feature.

debugrevlog: display total stored information This is an interesting statistis, so let's display it.