Revert "rust: update to 1.9.0."

This reverts commit 029a486e0e.

srcpkgs/rust/template

@@ -1,6 +1,6 @@
 # Template file for 'rust'
 pkgname=rust
-version=1.9.0
+version=1.8.0
 revision=1
 wrksrc="rustc-${version}"
 lib32disabled=yes
@@ -13,7 +13,7 @@ maintainer="Juan RP <xtraeme@voidlinux.eu>"
 homepage="http://www.rust-lang.org/"
 license="MIT, Apache-2.0"
 distfiles="https://static.rust-lang.org/dist/rustc-${version}-src.tar.gz"
-checksum=b19b21193d7d36039debeaaa1f61cbf98787e0ce94bd85c5cbe2a59462d7cfcd
+checksum=af4466147e8d4db4de2a46e07494d2dc2d96313c5b37da34237f511c905f7449
 
 do_configure() {
 	local _triplet