Auto merge of #1458 - alexcrichton:update, r=alexcrichton

Down with as_slice!

diff --cc src/cargo/ops/cargo_rustc/mod.rs
Simple merge

diff --cc src/cargo/ops/cargo_test.rs
Simple merge

diff --cc tests/test_cargo_doc.rs
Simple merge

diff --cc tests/test_cargo_test.rs
Simple merge