Fix shfmt formatting: align case patterns in _get_box_arch

Co-authored-by: electrocucaracha <2782150+electrocucaracha@users.noreply.github.com>
Agent-Logs-Url: https://github.com/electrocucaracha/lint-devstack/sessions/2373b90e-0d59-4f29-b775-59c3e1eaad56

Author: Copilot

ci/update_distros.sh

@@ -45,9 +45,9 @@ function _get_box_current_version {
 
 function _get_box_arch {
     case "$(uname -m)" in
-        x86_64) echo "amd64" ;;
-        aarch64) echo "arm64" ;;
-        *) uname -m ;;
+    x86_64) echo "amd64" ;;
+    aarch64) echo "arm64" ;;
+    *) uname -m ;;
     esac
 }