dispatch: change cwd when loading local config Previously, the `_getlocal` function would not correctly load the repo config when given a relative `rpath` and an alternate cwd via the `wd` parameter. Normally when `--cwd` is specified, hg changes to the given directory before attempting to load the local config (and therefore does not specify a `wd`). The only time the function is called with `wd` set is when hg is running as a command server (e.g., with chg), in which case each forked worker process will attempt to configure itself via `_getlocal` before responding to the client. When given a relative repo path, the worker fails to load the repo config, detects a config mismatch with the client, and enters a redirect/respawn loop. To fix this, we can simply change to the desired working directory during config loading. (Note that simply concatenating `wd` and `rpath` won't work in all cases. The repo path could be something more complicated than a simple relative path, such as a `union:` repo.)