docker: remove no cache dir flag
docker: remove no cache dir flag

* Fix from https://github.com/reanahub/reana-workflow-controller/issues/173.

diegodelemos/reana-job-controller,tiborsimko/reana-job-controller,tiborsimko/reana-job-controller,diegodelemos/reana-job-controller,reanahub/reana-job-controller,reanahub/reana-job-controller