Set yum priorities for public repos

Otherwise yum priorities plugin will ignore them

continuousintegration/docker/ctafrontend/cc7/etc/yum.repos.d-public/ceph.repo

@@ -4,3 +4,4 @@ baseurl=https://download.ceph.com/rpm-nautilus/el7/x86_64/
 gpgkey=file:///etc/pki/rpm-gpg/RPM-ASC-KEY-ceph
 gpgcheck=1
 enabled=1
+priority=1

continuousintegration/docker/ctafrontend/cc7/etc/yum.repos.d-public/oracle-instant-client.repo

@@ -4,3 +4,4 @@ baseurl=https://yum.oracle.com/repo/OracleLinux/OL7/oracle/instantclient/x86_64/
 gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-oracle
 gpgcheck=1
 enabled=1
+priority=1