revlog: always use a Rust index for REVLOGv1 if rustext is present...
revlog: always use a Rust index for REVLOGv1 if rustext is present
We are about to change classes such as `rustext.AncestorsIterator` to
take a Rust index, hence we cannot have the option not to use the Rust
index.
Note: this can be refined depending on whether we want to keep this
option or not. We will have to make two versions of `AncestorsIterator`
and its sibling to support REVLOGV2 and CHANGELOGv2 anyway.
Meanwhile, this is the simplest change to make the tests pass.