don't stay in the /usr directory

Author: Jorge Aparicio

ci/install.sh

@@ -15,18 +15,19 @@ install_binutils() {
 install_c_toolchain() {
     local dropbox_url=https://www.dropbox.com/sh/y9w7l5fk57vyikt/AABhZePp6j827VielYZvSa4Pa
 
+    pushd /usr
     case $TARGET in
         aarch64-unknown-linux-gnu)
             sudo apt-get install -y --no-install-recommends \
                  gcc-aarch64-linux-gnu libc6-arm64-cross libc6-dev-arm64-cross
             ;;
         mips-unknown-linux-gnu)
-            cd /usr
             curl -sL $dropbox_url/gcc-mips-linux-gnu.tar.xz?dl=1 | sudo tar -xJ
             ;;
         *)
             ;;
     esac
+    popd
 }
 
 install_rust() {