Auto merge of #5952 - dwijnand:fix-path-deep_dependencies_trigger_rebuild, r=alexcrichton
Fix path::deep_dependencies_trigger_rebuild often failing in CI
A shallow fix for `path::deep_dependencies_trigger_rebuild` in particular as it's failed my PRs often.
See https://github.com/rust-lang/cargo/pull/5935#issuecomment-417148372, and #5940 for the bigger picture.