This adds '|| true' to the curl command for gathering metrics from
prometheus exporters in the postrun job. After the move to
minikube for single node jobs, the headless services for the
kubernetes components no longer work as intended. The addition of
'|| true' allows the post run job to continue through the list
of services tied to the prometheus exporters without the task
failing outright
Change-Id: I56f0f56b799c3df9b2bd66a2c2044d71473606e3
84c6931c98