Auto merge of #10323 - ehuss:local-git-info, r=alexcrichton

Auto merge of #10323 - ehuss:local-git-info, r=alexcrichton

Use local git info for version.

#10178 caused an unintended change where cargo is being built twice in rust-lang/rust's CI.  It is being built once as a CLI, and a second time for RLS.  The cause is the `CFG_COMMIT_HASH` environment variable changes between those two builds (it is set for the tool being built).

The solution here is to grab the git information from cargo's own build script. This is guaranteed to always be in the `src/tools/cargo` directory for both tools.

This should help save a minute or two in the dist builders.