Auto merge of #5584 - boxdot:master, r=matklad
authorbors <bors@rust-lang.org>
Tue, 29 May 2018 09:41:12 +0000 (09:41 +0000)
committerbors <bors@rust-lang.org>
Tue, 29 May 2018 09:41:12 +0000 (09:41 +0000)
Verify that src dir wasn't modified by build.rs when publishing

Fixes issue #5073.

Implemented during RustFest Paris `impl days`.


Trivial merge