Auto merge of #5410 - klnusbaum:edition_5406, r=matklad
authorbors <bors@rust-lang.org>
Fri, 27 Apr 2018 15:14:03 +0000 (15:14 +0000)
committerbors <bors@rust-lang.org>
Fri, 27 Apr 2018 15:14:03 +0000 (15:14 +0000)
switch to using the --edition flag

Now that we have an `--edition` flag in the rust compiler, let's switch to using it.

fixes #5406


Trivial merge