dockerd-rootless.sh: add typo guard
`dockerd-rootless.sh install` is a common typo of `dockerd-rootless-setuptool.sh install`.
Now `dockerd-rootless.sh install` shows human-readable error.
# See the documentation for the further information: https://docs.docker.com/engine/security/rootless/
set -e -x
+case "$1" in
+ "check" | "install" | "uninstall")
+ echo "Did you mean 'dockerd-rootless-setuptool.sh $@' ?"
+ exit 1
+ ;;
+esac
if ! [ -w $XDG_RUNTIME_DIR ]; then
echo "XDG_RUNTIME_DIR needs to be set and writable"
exit 1
