[RHDM] OpenShift: remove installation of rh-maven33 in favor of rh-maven35

The following files install rh-maven33 into our RHPAM openshift images:

• https://github.com/jboss-container-images/rhdm-7-openshift-image/blob/rhdm70-dev/decisioncentral/image.yaml
• https://github.com/jboss-container-images/rhdm-7-openshift-image/blob/rhdm70-dev/kieserver/image.yaml

This is unnecessary as rh-maven35 is already installed via the included jboss-maven module:
https://github.com/jboss-openshift/cct_module/blob/master/jboss-maven/module.yaml

Additionally, there is an "Important" CVE regarding maven versions earlier than 3.5.