containers: workaround for ganesha package error on reef

Currently the tests on the released reef image fails due to an RPM
transaction error when updating nfs-ganesha. Since go-ceph doesn't
need ganesha packages to be up-to-date to ensure that
lib{cephfs,rados,rbd}-devel are installed we _temporarily_ disable
ganesha repo when running yum update.

Signed-off-by: John Mulligan <jmulligan@redhat.com>

testing/containers/ceph/Dockerfile

@@ -11,7 +11,7 @@ ENV GO_CEPH_VERSION=${GO_CEPH_VERSION:-$CEPH_VERSION}
 RUN true && \
     echo "Check: [ ${CEPH_VERSION} = ${GO_CEPH_VERSION} ]" && \
     [ "${CEPH_VERSION}" = "${GO_CEPH_VERSION}" ] && \
-    yum update -y && \
+    yum update -y --disablerepo=ganesha && \
     cv="$(rpm -q --queryformat '%{version}-%{release}' ceph-common)" && \
     yum install -y \
     git wget curl make \