Auto merge of #4139 - Keruspe:master, r=alexcrichton
Auto merge of #4139 - Keruspe:master, r=alexcrichton

Include rustc version in metadata

Followup to #4134
Fixes https://github.com/rust-lang/rust/issues/42483

vojtechkral/cargo,nipunn1313/cargo,tshepang/cargo,nipunn1313/cargo,vojtechkral/cargo,rustyhorde/cargo,eminence/cargo,tsurai/cargo,vojtechkral/cargo,tshepang/cargo,tsurai/cargo,rust-lang/cargo,durka/cargo,durka/cargo,rustyhorde/cargo,tshepang/cargo,durka/cargo,achanda/cargo,rustyhorde/cargo,tsurai/cargo,achanda/cargo,durka/cargo,tsurai/cargo,achanda/cargo,achanda/cargo,rust-lang/cargo,eminence/cargo,tsurai/cargo,eminence/cargo,tshepang/cargo,rust-lang/cargo,vojtechkral/cargo,eminence/cargo,nipunn1313/cargo,rust-lang/cargo,nipunn1313/cargo,rustyhorde/cargo