Auto merge of #3604 - froydnj:rich-version-info, r=alexcrichton

implement `cargo --version --verbose`

As suggested in #3584.  This is a bit underwhelming, and I'm unsure if some of the complexity in froydnj/cargo@775c900 is really warranted, but this series gets the job done.  Sample output when building with `configure` and `make`:

```
froydnj@hawkeye:~/src/cargo.git$ target/x86_64-unknown-linux-gnu/release/cargo --version
cargo-0.17.0-dev (ae4a4d8 2017-01-27)
froydnj@hawkeye:~/src/cargo.git$ target/x86_64-unknown-linux-gnu/release/cargo --version --verbose
cargo-0.17.0-dev (ae4a4d8 2017-01-27)
release: 0.17.0
commit-hash: ae4a4d8fc55bf7eca3d974f953dc61729e4a40db
commit-date: 2017-01-27
```

diff --cc src/cargo/lib.rs
index f0a93022a78b648461daa4b27abdd5bda3ab8ac4,b1e4198f8291050911d4684c0b5706872a004241..fbcb62c1e0fe140c5b316ecfb1bf1767c139ba37
mode 100644,100755..100755
--- 1/src/cargo/lib.rs
--- 2/src/cargo/lib.rs
+++ b/src/cargo/lib.rs