Auto merge of #2319 - alexcrichton:compat-12, r=brson
authorbors <bors@rust-lang.org>
Mon, 25 Jan 2016 21:50:36 +0000 (21:50 +0000)
committerbors <bors@rust-lang.org>
Mon, 25 Jan 2016 21:50:36 +0000 (21:50 +0000)
There hasn't actually ever been a request to maintain compatibility with older
stable Rust versions, and it's becoming a bit of a maintenance burden, so just
switch CI to run on stable Rust.


Trivial merge