[gnome-builder] rustup: update rustup.sh

[Christian Hergert <chergert src gnome org>]

commit 6c87a28e53eb4a83da1bfb48cb1b120e8c60b3ab
Author: Christian Hergert <chergert redhat com>
Date:   Wed Nov 22 17:17:42 2017 -0800

    rustup: update rustup.sh

 src/plugins/rustup/rustup.sh |    5 +----
 1 files changed, 1 insertions(+), 4 deletions(-)
---
diff --git a/src/plugins/rustup/rustup.sh b/src/plugins/rustup/rustup.sh
index 4156f37..7e089a1 100755
--- a/src/plugins/rustup/rustup.sh
+++ b/src/plugins/rustup/rustup.sh
@@ -36,6 +36,7 @@ FLAGS:
 OPTIONS:
         --default-host <default-host>              Choose a default host triple
         --default-toolchain <default-toolchain>    Choose a default toolchain to install
+        --default-toolchain none                   Do not install any toolchains
 EOF
 }
 
@@ -324,10 +325,6 @@ say() {
     echo "rustup: $1"
 }
 
-say_err() {
-    say "$1" >&2
-}
-
 err() {
     say "$1" >&2
     exit 1