Auto merge of #5541 - ehuss:fix-rustdoc-edition, r=alexcrichton
authorbors <bors@rust-lang.org>
Tue, 15 May 2018 17:53:20 +0000 (17:53 +0000)
committerbors <bors@rust-lang.org>
Tue, 15 May 2018 17:53:20 +0000 (17:53 +0000)
Fix passing --edition to rustdoc during doctests.

Fixes #5538


Trivial merge