Updating ose-libvirt-machine-controllers builder & base images to be …

…consistent with ART

Reconciling with https://github.com/openshift/ocp-build-data/tree/ce8ceaf63b458a778da06e96138bf50938597aab/images/ose-libvirt-machine-controllers.yml

Dockerfile.rhel7

@@ -1,11 +1,11 @@
-FROM registry.svc.ci.openshift.org/ocp/builder:rhel-8-golang-1.15-openshift-4.6 AS builder
+FROM registry.ci.openshift.org/ocp/builder:rhel-8-golang-1.15-openshift-4.7 AS builder
 RUN yum install -y libvirt-devel
 
 WORKDIR /go/src/github.com/openshift/cluster-api-provider-libvirt
 COPY . .
 RUN go build -o machine-controller-manager ./cmd/manager
 
-FROM registry.svc.ci.openshift.org/ocp/4.6:base
+FROM registry.svc.ci.openshift.org/ocp/4.7:base
 RUN INSTALL_PKGS=" \
       libvirt-libs openssh-clients genisoimage \
       " && \