Auto merge of #58584 - ehuss:update-cargo, r=alexcrichton

Update cargo

9 commits in 865cb70106a6b1171a500ff68f93ab52eea56e72..b33ce7fc9092962b0657b4c25354984b5e5c47e4
2019-02-10 15:49:37 +0000 to 2019-02-19 18:42:50 +0000
- Don't retry invalid credentials from git credential helpers (rust-lang/cargo#6681)
- Fix some typos in resolver tests (rust-lang/cargo#6682)
- Add an unstable option to build proc macros for both the host and the target (rust-lang/cargo#6547)
- Test cases proving RUSTC_WRAPPER can be a relative path (rust-lang/cargo#6638)
- Add support for Azure DevOps (rust-lang/cargo#6264)
- Update docs for removed `patch` restriction. (rust-lang/cargo#6663)
- Fix incorrect help message (rust-lang/cargo#6555)
- Stabilize Alternative Registries (rust-lang/cargo#6654)
- Having a [patch] section when publishing is not an error (rust-lang/cargo#6535)