Auto merge of #2352 - alexcrichton:new-snapshots, r=alexcrichton

The current snapshot is *super* old (305 days), but as of a few minutes ago it looks like all builds are going to fail with:

```
    Updating registry `https://github.com/rust-lang/crates.io-index`
Failed to parse registry's information for: url

Caused by:
  the given version requirement is not implemented, yet
```

I believe this is because ages ago the semver library wasn't quite fully implemented. The [most recently published url crate](https://crates.io/crates/url/0.5.4) has a version requirement that looks like `>= foo, < bar` which I believe was implemented at some point in the last year.

As a result if we want to keep building Cargo on bors we'll have to upgrade the snapshot, so this does so! For now just pick the absolute newest Cargo to run with and we reset the counters!