Because of the Centos Stream 8 EOL, the libvirt-installer image is failing to build in CI.

[1] https://blog.centos.org/2023/04/end-dates-are-coming-for-centos-stream-8-and-centos-linux-7/

4.15

always

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                [5/5] STEP 6/16: RUN yum update -y &&     yum install --setopt=tsflags=nodocs -y     genisoimage     gettext     google-cloud-sdk-365.0.1     libvirt-client     libvirt-libs     nss_wrapper     openssh-clients &&     yum clean all && rm -rf /var/cache/yum/*
                CentOS Stream 8 - AppStream                     187  B/s |  38  B     00:00    
                Error: Failed to download metadata for repo 'appstream': Cannot prepare internal mirrorlist: No URLs in mirrorlist
                error: build error: building at STEP "RUN yum update -y &&     yum install --setopt=tsflags=nodocs -y     genisoimage     gettext     google-cloud-sdk-365.0.1     libvirt-client     libvirt-libs     nss_wrapper     openssh-clients &&     yum clean all && rm -rf /var/cache/yum/*": while running runtime: exit status 1

For now only 4.15 is affected but I expect older releases will be hit when centos 7 goes EOL at 30 Jun 2024.