Rust 0.8

Closes Homebrew/homebrew#22867.

Signed-off-by: Adam Vandenberg <flangy@gmail.com>

Formula/rust.rb

@@ -2,8 +2,8 @@ require 'formula'
 
 class Rust < Formula
   homepage 'http://www.rust-lang.org/'
-  url 'http://static.rust-lang.org/dist/rust-0.7.tar.gz'
-  sha256 '0b88b8a4489382e0a69214eaab88e2e7c316ec33c164af0d3b53630b17590df0'
+  url 'http://static.rust-lang.org/dist/rust-0.8.tar.gz'
+  sha256 '42f791ab1537357fe0f63d67ffe6bcb64ecf16b2bd3f1484ab589823f5914182'
 
   head 'https://github.com/mozilla/rust.git'
 
@@ -22,7 +22,7 @@ class Rust < Formula
 
   def test
     system "#{bin}/rustc"
-    system "#{bin}/rustdoc"
-    system "#{bin}/rustpkg"
+    system "#{bin}/rustdoc -h"
+    system "#{bin}/rustpkg -v"
   end
 end