ci/setup: Minor cleanups

- Use bash strict mode more consistently
- Drop the error redirections which can mask problems as
  recommended by AI

Signed-off-by: Colin Walters <walters@verbum.org>

.github/actions/bootc-ubuntu-setup/action.yml

@@ -25,22 +25,22 @@ runs:
     - name: Free up disk space on runner
       shell: bash
       run: |
+        set -xeuo pipefail
         sudo df -h
         unwanted=('^aspnetcore-.*' '^dotnet-.*' '^llvm-.*' 'php.*' '^mongodb-.*' '^mysql-.*'
                   azure-cli google-chrome-stable firefox mono-devel)
         for x in ${unwanted[@]}; do
-          sudo apt-get remove -y $x > /dev/null
+          sudo apt-get remove -y $x
         done
         # Start other removal operations in parallel
-        sudo docker image prune --all --force > /dev/null &
-        sudo rm -rf /usr/share/dotnet /opt/ghc /usr/local/lib/android &
-        # Wait for all background processes to complete
-        wait
+        sudo docker image prune --all --force
+        sudo rm -rf /usr/share/dotnet /opt/ghc /usr/local/lib/android
         sudo df -h
     # This is the default on e.g. Fedora derivatives, but not Debian
     - name: Enable unprivileged /dev/kvm access
       shell: bash
       run: |
+        set -xeuo pipefail
         echo 'KERNEL=="kvm", GROUP="kvm", MODE="0666", OPTIONS+="static_node=kvm"' | sudo tee /etc/udev/rules.d/99-kvm4all.rules
         sudo udevadm control --reload-rules
         sudo udevadm trigger --name-match=kvm