Removes Centos Dockerfile for "repo-client" container
Removes Centos Dockerfile for "repo-client" container

This image is not being built with the other Postgres Operator
images. There are no other references to this file in the PGO
codebase and there are no customers using this container. This
Dockerfile is being removed along with all references to the file.

CrunchyData/postgres-operator,CrunchyData/postgres-operator