Auto merge of #4493 - alexcrichton:verify-tarballs, r=matklad
authorbors <bors@rust-lang.org>
Sun, 17 Sep 2017 08:38:04 +0000 (08:38 +0000)
committerbors <bors@rust-lang.org>
Sun, 17 Sep 2017 08:38:04 +0000 (08:38 +0000)
Verify tarballs don't extract into other directories

Continuation of https://github.com/rust-lang/crates.io/pull/1054 except support on the Cargo side of things


Trivial merge