Update stage0 bootstrap compiler

We've got a freshly minted beta compiler, let's update to use that on nightly!
This has a few other changes associated with it as well

* A bump to the rustc version number (to 1.19.0)
* Movement of the `cargo` and `rls` submodules to their "proper" location in
  `src/tools/{cargo,rls}`. Now that Cargo workspaces support the `exclude`
  option this can work.
* Updates of the `cargo` and `rls` submodules to their master branches.
* Tweak to the `src/stage0.txt` format to be more amenable for Cargo version
  numbers. On the beta channel Cargo will bootstrap from a different version
  than rustc (e.g. the version numbers are different), so we need different
  configuration for this.
* Addition of `dev` as a readable key in the `src/stage0.txt` format. If present
  then stage0 compilers are downloaded from `dev-static.rust-lang.org` instead
  of `static.rust-lang.org`. This is added to accomodate our updated release
  process with Travis and AppVeyor.

1 files changed, 0 insertions, 1 deletions

diff --git a/src/libstd/lib.rs b/src/libstd/lib.rs
index 70225da5f33..a4c3b276efd 100644
--- a/src/libstd/lib.rs
+++ b/src/libstd/lib.rs
@@ -318,7 +318,6 @@
 #![feature(unwind_attributes)]
 #![feature(vec_push_all)]
 #![cfg_attr(test, feature(update_panic_count))]
-#![cfg_attr(stage0, feature(pub_restricted))]
 #![cfg_attr(test, feature(float_bits_conv))]
 
 // Explicitly import the prelude. The compiler uses this same unstable attribute