Auto merge of #2685 - mkroman:master, r=alexcrichton
authorbors <bors@rust-lang.org>
Tue, 17 May 2016 16:00:28 +0000 (09:00 -0700)
committerbors <bors@rust-lang.org>
Tue, 17 May 2016 16:00:28 +0000 (09:00 -0700)
Fix `cargo test --doc` not testing examples

When running cargo doc --test in a project folder, cargo does not test documentation examples, it only builds the project and exits.

Refer to issue #2684


Trivial merge