Auto merge of #2124 - RalfJung:rustup-toolchain, r=RalfJung

rustup-toolchain: also prepare toolchain for vscode

This is a work-around for rust-lang/cargo#10096.

Author: bors

rustup-toolchain

@@ -44,3 +44,7 @@ rustup override set miri
 
 # Cleanup.
 cargo clean
+
+# Call 'cargo metadata' on the sources in case that changes the lockfile
+# (which fails under soem setups when it is done from inside vscode).
+cargo metadata --format-version 1 --manifest-path "$(rustc --print sysroot)/lib/rustlib/rustc-src/rust/compiler/rustc/Cargo.toml" >/dev/null