Fix the nop hack

I hate myself

Signed-off-by: Chmouel Boudjnah <chmouel@redhat.com>

openshift/ci-operator/tekton-images/nop/Dockerfile

@@ -5,6 +5,6 @@ FROM registry.access.redhat.com/ubi8/ubi-minimal:latest
 # distroless. We want to mimic as much as possible the distroless image but
 # still be based on a UBI, it's not pretty but let's hope we can remove this when
 # we get https://github.com/tektoncd/pipeline/issues/1347
-RUN cp /bin/true /tmp && rm -f /usr/bin/* /usr/sbin/* /bin/* /sbin/*;cp -v /tmp/true /bin/true
+RUN for i in /usr/bin/* /usr/sbin/* /bin/* /sbin/*;do [[ $i == /bin/true ]] && continue;rm -v $i;done
 
 ENTRYPOINT ["/bin/true"]