revlog: explicitely pass the "indexfile" parameter Most of this was already done when introducing the `target` parameter, but some remained. Having "indexfile" passed explicitely will help us to change the way we address a revlog later in the stack. With the introduction of more generic `docket`, the entry point will not necessarly be `xxx.i` file, and the actual index files will have a variable name. Differential Revision: https://phab.mercurial-scm.org/D10561