The non-native capnp was trying to fetch the wrong file.
Without this, "make -C depends MULTIPROCESS=1 download" is broken.
Presumably it breaks with the download target because the dependency graph is
flattened. It manages to work if native_capnp is encountered first because it
will then be found in the cache.
This reverts the changes made in merge commit
1b307613604883daea4913a65da30ae073c9dc4d:
This reverts commit b919efadff3d0393f4a8c3c1dc735f7ac5c665bb.
This reverts commit d54f64c6c700be0604190f52c84fc5f1cdd9f02f.
This reverts commit 787f40668dc15980c3d6de028d7950c08175d84a.
This reverts commit d6306466626635e6fee44385e6a688c8dc118eb5.
This reverts commit e6e44eedd56ecaf59f3fabf8e07ab7dee0ddb1b6.
