Update Rust to 1.7

toolset/setup/linux/languages/rust.sh

@@ -5,10 +5,10 @@ RETCODE=$(fw_exists $IROOT/rust.installed)
   source $IROOT/rust.installed;
   return 0; }
 
-fw_get -O https://static.rust-lang.org/dist/rust-1.6.0-x86_64-unknown-linux-gnu.tar.gz
-fw_untar rust-1.6.0-x86_64-unknown-linux-gnu.tar.gz
+fw_get -O https://static.rust-lang.org/dist/rust-1.7.0-x86_64-unknown-linux-gnu.tar.gz
+fw_untar rust-1.7.0-x86_64-unknown-linux-gnu.tar.gz
 (
-	cd rust-1.6.0-x86_64-unknown-linux-gnu
+	cd rust-1.7.0-x86_64-unknown-linux-gnu
 	./install.sh --prefix=$IROOT/rust
 )